microDXP - XIA...microDXP Rapid Development Kit User’s Manual Release 2.5.0 March 17, 2010...

microDXP Rapid Development Kit

User’s Manual Release 2.5.0

March 17, 2010

MicroComU v2.10 Rev 12231

MicroCOM Hardware Revision: B

MicroDXP Hardware Revision: F

Micromanager Software Revision: 2.3.x

XIA LLC

31057 Genstar Rd. Hayward, CA 94544 USA

Tel: (510) 401-5760; Fax: (510) 401-5761 http://www.xia.com/

Information furnished by XIA LLC (XIA) is believed to be accurate and reliable. However, no responsibility is assumed by XIA for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of XIA. XIA reserves the right to change specifications at any time without notice. Patents have been applied for to cover various aspects of the design of the DXP Digital X-ray Processor

Manual: MicroDXP Rapid Development Kit mdo-RDK-MAN-2.5.0

Safety ............................................................................................................................. iv Power Source ................................................................................................. iv Detector and Preamplifier Damage ................................................................ iv Servicing and Cleaning................................................................................... iv

WARRANTY .................................................................................................................... v Contact Information:......................................................................................... v

Manual Conventions..................................................................................................... vi 1 Overview................................................................................................................... 1

1.1 Rapid Development Kit ....................................................................................1 1.1.1 Components Included.........................................................................1 1.1.2 Hardware Features .............................................................................1

1.2 Software Features:...........................................................................................2 1.2.1 Configuration.......................................................................................2 1.2.2 Spectrum Acquisition ..........................................................................2 1.2.3 Analysis and Statistics ........................................................................2 1.2.4 Diagnostics .........................................................................................3

1.3 System Requirements:.....................................................................................3 1.3.1 USB Rapid Development Kit System Requirements ..........................3 1.3.2 RS232 Rapid Development Kit System Requirements ......................3 1.3.3 Host Computer or PDA: ......................................................................3 1.3.4 Detector/Preamplifier: .........................................................................3 1.3.5 Power Requirements ..........................................................................4 1.3.6 Operating Environment.......................................................................4 1.3.7 Regulatory Compliance ......................................................................5

1.4 Support ............................................................................................................5 1.4.1 Software and Firmware Updates ........................................................5 1.4.2 Related Documentation ......................................................................5 1.4.3 Email and Phone Support...................................................................6 1.4.4 Customer and User Feedback............................................................7 1.4.5 The Accelerated DevelOPmenT (ADOPT) Program ..........................7

2 USB and RS232 RDK Hardware Setup .................................................................. 9 2.1 MicroDXP and MicroComU Hardware Settings...............................................9

2.1.1 Power Supply Setting..........................................................................9 2.1.2 Preamplifier Type Selection..............................................................10 2.1.3 Input Signal Attenuation....................................................................10

1. Making Connections ......................................................................................11 2.1.4 MicroComU to microDXP Connection ..............................................11 2.1.5 USB...................................................................................................11 2.1.6 Detector and Preamplifier .................................................................11 2.1.7 Power................................................................................................11

3 Using the microManager 2.3 Software ................................................................13 3.1 Installation......................................................................................................13

3.1.1 First Steps.........................................................................................13 3.1.2 After Installation ................................................................................13 3.1.3 File Locations....................................................................................13 3.1.4 Support .............................................................................................14

3.2 Starting Up the First Time..............................................................................14 3.2.1 USB / COM Port Configuration .........................................................14 3.2.2 Firmware Auto-Update......................................................................15

3/18/2010 i


3.3 A Quick Tour of microManager 2.3................................................................15 3.3.1 Windows and Panels ........................................................................15 3.3.2 Apply, Undo and Save ......................................................................17 3.3.3 Preview of the Setup Process...........................................................17 3.3.4 GLOBSETs, PARSETs and GENSETs ............................................17

3.4 Detector/Preamplifier Settings .......................................................................18 3.4.1 Viewing the Preamplifier Signal ........................................................18 3.4.2 Setting the Polarity............................................................................19 3.4.3 Setting the Reset Delay (Reset-Type Preamplifiers)........................19 3.4.4 Setting the Decay Constant (RC-Feedback Preamplifiers) ..............19

3.5 Preliminary MCA (GENSET) Settings............................................................20 3.5.1 Analog Gain vs. Digital Attenuation ..................................................20 3.5.2 Preliminary Base Gain Setting..........................................................21 3.5.3 Setting the Dynamic Range ..............................................................22 3.5.4 MCA Settings ....................................................................................22

3.6 Spectrum Acquisition .....................................................................................23 3.6.1 ROI Selection....................................................................................24 3.6.2 Base Gain Calibration.......................................................................25

3.7 Peaking Time (PARSET) Optimization ..........................................................26 3.7.1 Threshold Settings ............................................................................27 3.7.2 Fine Gain Trim ..................................................................................28 3.7.3 Optimization of Remaining PARSETs ..............................................28 3.7.4 Advanced Optimizations ...................................................................30 3.7.5 Viewing the run statistics ..................................................................33 3.7.6 Saving a spectrum ............................................................................34

3.8 Diagnostics ....................................................................................................34 3.8.1 Board Information .............................................................................34 3.8.2 Handel Log File.................................................................................35 3.8.3 The ADC Trace Panel.......................................................................35 3.8.4 Identifying Noise ...............................................................................35 3.8.5 Measuring the RC Decay Constant (RC Preamplifiers ONLY) ........36 3.8.6 Tracking Steps (Reset-Type Preamplifiers ONLY)...........................38 3.8.7 Baseline Acquisition..........................................................................39 3.8.8 The Baseline Threshold....................................................................39 3.8.9 Number of Samples in the Baseline Average...................................41 3.8.10 The Reset Interval .........................................................................42 3.8.11 The Baseline Cut ...........................................................................43 3.8.12 The DSP Parameters Panel ..........................................................44

2. The XUP Utility...............................................................................................44 3.8.13 Saving a Master Parameter Set ....................................................45 3.8.14 Downloading an XUP or Backup File ............................................45

Appendices...................................................................................................................46 Appendix A MicroDXP Specification ....................................................................46

A.1 Board Dimensions and Mounting ............................................................46 A.2 Preamplifier Type Selector Switch ..........................................................46 A.3 Input Signal Attenuation ..........................................................................47 A.4 Connector Locations and Pinouts ...........................................................47 A.5 Power Supplies........................................................................................51

Appendix B System Development Outline ...........................................................53 Appendix C Auxiliary I/O Functions......................................................................55

C.1 GATE* Input ............................................................................................55

3/18/2010 ii


C.2 Configurable I/O Lines ............................................................................55 C.3 External Interrupt.....................................................................................55 C.4 I2C Bus ....................................................................................................55

3/18/2010 iii


Safety

Please take a moment to review these safety precautions. They are

provided both for your protection and to prevent damage to your microDXP / microCOM / MicroComU boards and connected equipment. This safety information applies to all operators and service personnel.

Power Source The microDXP RS232 Rapid Development Kit includes a wall-

mounted power supply intended to operate from an AC mains supply voltage of 120VAC at 60Hz. Use of this development kit with any other mains voltage or power supply could damage the unit and nullify the product warranty. Refer to Chapter 2.USB and RS232 RDK Hardware Setup of this manual for instructions on installing the power supply.

The microDXP USB Rapid Development Kit includes a wall-mounted power supply intended to operate from an AC power supply in the 100VAC to 240VAC range at 50Hz or 60Hz. Use of this development kit with AC voltage outside these specifications could damage the unit and nullify the product warranty. Refer to Chapter 3.USB and RS232 RDK Hardware Setup of this manual for instructions on installing the power supply.

Detector and Preamplifier Damage Because the microDXP does not provide power for the detector or

preamplifier there is little risk of damage to either resulting from the microDXP itself. Nonetheless, please review all instructions and safety precautions provided with these components before powering a connected system.

Servicing and Cleaning To avoid personal injury, and/or damage to the microDXP /

microCOM / MicroComU boards or connected equipment, do not attempt to repair or clean these units. These boards are warranted against all defects for one (1) year. Please contact the factory or your distributor before returning items for service.

3/18/2010 iv


WARRANTY

XIA LLC warrants that this product will be free from defects in

materials and workmanship for a period of one (1) year from the date of shipment. If any such product proves defective during this warranty period, XIA LLC, at its option, will either repair the defective products without charge for parts and labor, or will provide a replacement in exchange for the defective product.

In order to obtain service under this warranty, Customer must notify XIA LLC of the defect before the expiration of the warranty period and make suitable arrangements for the performance of the service.

This warranty shall not apply to any defect, failure or damage caused by improper uses or inadequate care. XIA LLC shall not be obligated to furnish service under this warranty a) to repair damage resulting from attempts by personnel other than XIA LLC representatives to repair or service the product; or b) to repair damage resulting from improper use or connection to incompatible equipment.

THIS WARRANTY IS GIVEN BY XIA LLC WITH RESPECT TO

THIS PRODUCT IN LIEU OF ANY OTHER WARRANTIES, EXPRESSED OR IMPLIED. XIA LLC AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF MERCHANTABILITYOR FITNESS FOR A PARTICULAR PURPOSE. XIA LLC’S RESPONSIBILITY TO REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY. XIA LLC AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER XIA LLC OR THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.

Contact Information:

XIA LLC 31057 Genstar Rd. Hayward, CA 94544 USA [email protected] (for microDXP or microCOM or MicroComU hardware support) [email protected] (for microManager software support)

(510) 401-5760

3/18/2010 v

mailto:[email protected]



Manual Conventions

Through out this manual we will use the following conventions:

Convention Description Example » The » symbol leads you

through nested menu items, DAQExplorer items, and dialog box options.

The sequence File»Page Setup»Options directs you to pull down the File menu, select the Page Setup item, and choose Options from the sub menu.

Bold Bold text denotes items that you must select or click on in the software, such as menu items, and dialog box options.

...expand the Run Control section of the DAQExplorer to access the run presets.

[Bold] Bold text within [ ] denotes a command button.

[Start Run] indicates the command button labeled Start Run.

monospace Items in this font denote sections of code, file contents, and syntax examples.

Setup.exe refers to a file called “setup.exe” on the host computer.

“window” Text in quotation refers to window titles, and quotations from other sources

“Options” indicates the window accessed via Tools»Options.

Italics Italic text denotes a new term being introduced , or simply emphasis

peaking time refers to the length of the slow filter. ...it is important first to set the energy filter Gap so that SLOWGAP to at least one unit greater than the preamplifier risetime...

<Key> <Shift-Alt-Delete> or <Ctrl+D>

Angle brackets denote a key on the keybord (not case sensitive). A hyphen or plus between two or more key names denotes that the keys should be pressed simultaneously (not case sensitive).

<W> indicates the W key <Ctrl+W> represents holding the control key while pressing the W key on the keyboard

Bold italic Warnings and cautionary text.

CAUTION: Improper connections or settings can result in damage to system components.

CAPITALS CAPITALS denote DSP parameter names

SLOWLEN is the length of the slow energy filter

3/18/2010 vi


1 Overview

XIA LLC now sells two versions of the microDXP Rapid Development Kit. The RS232 Rapid Development Kit is the older product and supports an RS232 (COM port) connection to a PC or PDA using the microCOM board. The recently introduced USB Rapid Development Kit supports a USB 2.0 high speed interface to a PC using the MicroComU board. XIA LLC recommends the USB Rapid Development Kit for new customers.

This manual describes both Rapid Development Kits. Where necessary, a distinction will be drawn between the two kits. But for many aspects of the operation, including software operation, both kits behave the same.

The microDXP Rapid Development Kits consist of hardware interfaces with standardized connections and evaluation software. The kits enable rapid design of systems incorporating the Micro Digital X-ray Processor (microDXP). This brief manual is intended to get customers up and running quickly. Please refer to the MicroDXP Technical Reference Manual, for a complete description of all microDXP commands and features. It is available online at:

http://www.xia.com/microDXP.html

With these kits the customer can immediately evaluate standard functions of the microDXP and rapidly build their own prototype spectroscopy systems. The hardware in the kits does provide access to the auxiliary I/O functions of the microDXP, though for more demanding applications additional hardware will be required. Such development efforts will also require customized firmware and thus extended XIA support.

1.1 Rapid Development Kit

1.1.1 Components Included • MicroComU companion board • Wall mounted AC power supply, suitable for 100VAC to 240VAC,

50Hz or 60Hz. Compatible with AC power standards and AC plug standards in North America, Japan, UK, Europe, and Australia.

• 6’ USB A male to USB Mini-B cable for connecting the MicroComU / microDXP board set to a PC.

• 6’ custom DB9 to 3-pin connector for RS232 communication (part number CAB-DB9-3POS).

• 6” analog input cable BNC adapter • microDXP Rapid Development Kit Manual (this document) • microDXP Technical Reference Manual • MicroComU Technical Reference Manual • MicroManager evaluation software

1.1.2 Hardware Features The MicroComU companion board provides these functions:

3/18/2010 1



• Implements a standard USB 2.0 high speed connection between the PC and the MicroComU / microDXP board set.

• Provides all the necessary power supplies needed by the microDXP board. The MicroComU / microDXP board set may be powered by the USB port itself, or by a single external DC supply, such as the AC wall adapter provided in this Rapid Development Kit.

• An RS232 interface between the PC / PDA and the microDXP board. This is to support customers already using the RS232 interface in their applications.

• Hardware GATE input and auxiliary digital I/O lines via board-to-wire connector. Note: Use of the auxiliary digital I/O lines will require special firmware.

• I2C signals via board-to-wire connector. This allows additional I2C peripherals (ie. high voltage supplies, DACs, temperature sensors, EEPROMs, etc.) to be added to the system. Note: Use of the I2C connector will require special firmware.

• SMA signal input connector, which supplements the other options available on the microDXP board itself: 2-pin, Lemo, BNC. Note: Customers wishing to use the SMA signal input connector are requested to contact XIA LLC to inquire about ordering the compatible variant of the microDXP board.

• Includes necessary power supplies and cabling to integrate the microDXP into a typical system

• More complete information on the MicroComU board, including detailed dimensions, connector locations, connector pin assignments, etc. may be found in the MicroComU Technical Reference Manual, which is available online at:


1.2 Software Features: The microManager software supports microDXP configuration,

spectrum acquisition and analysis, and diagnostic procedures:

1.2.1 Configuration • Detector/Preamplifier settings • Peaking time optimization (via PARSETs) • MCA format (via the GENSET) • Update microDXP firmware using the XUP utility • Settings import/export for multiple identical systems

1.2.2 Spectrum Acquisition • Parameter-set-based acquisition • Preset fixed-length runs • Offline calibration • Variable bin depth for faster readout

1.2.3 Analysis and Statistics • Dynamic Regions of Interest (ROI) • Gaussian Fits to multiple ROIs • Output statistics: ICR, OCR, realtime, deadtime

3/18/2010 2



• Panning and Zooming to examine spectrum features • Linear and Logarithmic displays • Export Spectra for additional analysis

1.2.4 Diagnostics • Digital oscilloscope • Baseline histogram and history views • DSP Parameter Editor

1.3 System Requirements:

1.3.1 USB Rapid Development Kit System Requirements • Pentium II or better class PC running Windows Vista or XP with free

USB 1.1 or USB 2.0 (preferred) port. • x-ray or γ-ray detector and preamplifier w/ power supplies

--- or a spectroscopy-grade pulse generator • BNC analog signal cable, to match the included adapter • 100VAC to 240VAC at 50Hz or 60Hz AC voltage mains OR high-

power capable USB port on PC or on a powered USB hub.

1.3.2 RS232 Rapid Development Kit System Requirements • x86 or Pentium or better class PC with free RS-232 serial (COM) port

or PDA with RS232 serial port (or use commonly available USB to serial port adapter)

• x-ray or γ-ray detector and preamplifier w/ power supplies --- or a spectroscopy-grade pulse generator

• BNC analog signal cable, to match the included adapter • 100-240 VAC/50-60Hz AC voltage mains

1.3.3 Host Computer or PDA: The microDXP communicates with a host computer or PDA via USB

or RS-232 serial communications. A full description of the command set can be found in the microDXP RS-232 Communications Specification, available online at:


1.3.4 Detector/Preamplifier: The microDXP accommodates nearly all energy-dispersive detector

preamplifier signals. The two primary capacitor-discharge topologies, pulsed-reset and resistive-feedback, are supported. The voltage compliance range in the DXP analog circuitry imposes in the following constraints:

Preamplifier signal and power specifications must be verified.

Parameter Minimum Maximum Typical X-ray pulse-height 250uV 375mV 25mV Input voltage range - ±3.9V

±7.8V* ±2.5V

Table 1.1: Analog input signal constraints for pulsed-reset preamplifiers.

3/18/2010 3



Parameter Minimum Maximum Typical X-ray pulse-height 250uV 625mV 100mV Input voltage range - ±3.9V

±7.8V* ±2.5V

Decay time τ 100ns infinity 50us

Table 1.2: Analog input signal contraints for RC-feedback preamplifiers. *See §2.1.3 for details about setting the input attenuation.

If the output voltage of your preamplifier exceeds this range, the

microDXP must be modified before connections are made. Please contact XIA to discuss non-standard input voltage ranges.

1.3.5 Power Requirements

1.3.5.1 Rapid Development Kit Power Requirements

The MicroComU companion board handles all power supply generation, producing all required voltages at the required currents and noise quality, to satisfy the requirements of the microDXP board. The only caveat is that the microDXP board must be configured to use its on-board LDO linear regulators for the analog voltages. However, this is the default configuration of the microDXP board.

The MicroComU / microDXP board set may be powered from either a high-power capable USB port (such as a USB port on a PC or a port on a powered USB hub) or from a single external 5.0VDC to 5.5VDC supply, such as the AC wall adapter provided with the USB Rapid Development Kit. This AC wall adapter is compatible with 100VAC to 240VAC, at 50Hz or 60Hz, and works with plug standards in North America, Japan, UK, Europe, and Australia. Additional details of the MicroComU power supply requirements are described in the MicroComU Technical Reference Manual available online at:


1.3.6 Operating Environment Temperature Range: 0° C - 50° C Maximum Relative Humidity: 75%, non-condensing. Maximum Altitude: 3,000 meters Pollution degree 2 Not rated for use in high electromagnetic fields. Not rated for use in environments with measurable neutron flux. Neutron flux will cause permanent damage to silicon crystals and permanently degrade or impair the performance of this system. The components on the MicroComU and microCOM boards are not radiation hardened. Although there should not be a problem operating them in environments with modest gamma or X-ray flux, above a certain level this radiation will start to cause bit errors in the digital components. If necessary, please contact XIA LLC to discuss a proposed radiation environment.

3/18/2010 4



1.3.7 Regulatory Compliance The MicroComU board included with the USB Rapid Development

Kit is RoHS compliant.

1.4 Support A unique benefit of dealing with a small company like XIA is that the

same people who designed them often provide the technical support for our sophisticated instruments. Our customers are thus able to get an in-depth technical advice on how to fully utilize our products within the context of their particular applications. Please read through this brief chapter before contacting us.

XIA LLC 31057 Genstar Rd. Hayward, CA 94544 USA (510) 401-5760 Hardware Support: [email protected] Support: [email protected]

1.4.1 Software and Firmware Updates Check for firmware and software updates at: http://www.xia.com/microDXP.html

It is important that the DXP unit is driven by the most recent software/firmware combination, since most problems are actually solved at the firmware and software level. The first time a microDXP board is operated via the microManager 2.1 software some of the firmware will automatically be updated and a backup of existing firmware created. Please also check for the most up to date standard versions of the microDXP software and firmware at:


Please contact XIA at [email protected] if you are running semi-custom or proprietary firmware code. (Note: it is not a bad idea to make backup copies of your existing software and firmware before you update).

1.4.1.1 XUP Utility and Firmware Updates

Firmware updates will be provided in the XUP format, which is only supported by microManager. MicroManager’s XUP utility also supports the import and export of parameter settings to and from non-volatile memory, such that multiple identical systems can easily be configured. The XUP utility also automatically creates backups of existing firmware and parameter settings in the same format such that prior hardware states can be recovered.

1.4.2 Related Documentation As a first step in diagnosing a problem, it is sometimes helpful to

consult the most recent data sheets and user manuals for a given DXP product, available in the Adobe Portable Document Format (PDF) from the XIA web site. Since these documents may have been updated since the DXP unit was purchased, they may contain information that could help solving a problem in question. All manuals, datasheets, and application notes, as well as software and firmware downloads can be found on at:


3/18/2010 5






In order to request printed copies, please send an e-mail to [email protected], or call the company directly. In particular, we recommend that you download the following documents:

Rapid Development Kit User Manual (to check for updated versions of this document) – All users MicroDXP Technical Reference Manual – All users MicroComU Technical Reference Manual -- Users of the USB Rapid Development Kit MicroDXP RS-232 Communications Specification – Users who wish to develop their own software and/or hardware

1.4.3 Email and Phone Support The microDXP comes with one year of email and phone support.

Support can be renewed for a nominal fee. Please call XIA if your support agreement has expired.

The XIA Digital Processors (DGF & DXP) are digitally controlled, high performance products for X-ray and gamma-ray spectroscopy. All settings can be changed under computer control, including gains, peaking times, pileup inspection criteria, and ADC conversion gain. The hardware itself is very reliable. Most problems are not related to hardware failures, but rather to setup procedures and to parameter settings. XIA's DXP software includes several consistency checks to help select the best parameter values. However, due to large number of possible combinations the user may occasionally request parameter values which conflict among themselves. This can cause the DXP unit to report data which apparently make no sense (such as bad peak resolution or even empty spectra). Each time a problem is reported to us, we diagnose it and include necessary modifications in the new versions of our DXP control programs, as well as add the problem description to the FAQ list.

Submitting a problem report:

XIA encourages customers to report any problems encountered using any of our software. Unfortunately, due to limited resources XIA is unable to handle bug reports over the phone. In most cases, the XIA engineering team will need to review the bug information and run tests on their hardware before being able to respond.

All software-related bug reports should be emailed to [email protected] and should contain the following information, which will be used by our technical support personnel to diagnose and solve the problem:

• Your name and organization • Brief description of the application (type of detector, relevant

experimental conditions...etc.) • XIA hardware name and serial number • Version of the library (if applicable) • OS • Description of the problem; steps taken to re-create the bug

3/18/2010 6



• Supporting data: The most important are digital settings of the spectrometer unit, i.e., the values of the DSP parameters such as the decimation, filter length, etc. The values of these parameters can be captured into text file in microManager as described in §3.8.1. Please attach a copy of this file if possible. Capturing an oscilloscope image of the preamp output will be extremely helpful. This can done with the diagnostic tool included in microManager.

For general questions and DXP hardware issues please send email to:

[email protected]

1.4.4 Customer and User Feedback XIA strives to keep up with the needs of our users. Please send us your

feedback regarding the functionality and usability of the microDXP and microManager software. In particular, we are considering the following development issues:

1.4.4.1 Export File Formats

We would like to directly support as many spectrum file formats as possible. If we do not yet support it, please send your specification to

[email protected]

1.4.4.2 Fast Communications

Currently the hardware supports three communications interfaces: an RS-232 serial port, a synchronous DSP serial port and IDMA parallel DSP access. Only the RS-232 interface and recently the IDMA parallel DSP interface have been implemented thus far in generally available software and firmware. Please inquire about use of the DSP serial port interface.

1.4.4.3 Hardware Interfaces for Production

Recently the MicroComU companion board has been introduced in order to provide customers with a USB 2.0 high speed interface to the microDXP and power supply generation for the microDXP, all in a form factor close to the size of the microDXP itself. We are interested in how well the new MicroComU board satisfies customer requirements and/or what improvements are desired.

1.4.5 The Accelerated DevelOPmenT (ADOPT) Program The ADOPT program is a support plan for users developing custom

software using any of our driver libraries. It is intended for those who wish to get direct access to the XIA software team and obtain hands-on training in the use of XIA software tools as a method of reducing overall software development time.

The standard ADOPT package provides 12 months of support divided as follows:

• 1 month: on-site support and priority phone/email support.

3/18/2010 7



• 11 months: priority phone/email support. The specific number of hours for on-site support and priority

phone/email support depend on the driver library being used. Typically, the person who will be doing the majority of the development will visit XIA for a hands-on tutorial with the XIA software team. The visitor will be encouraged to work at XIA for anywhere from a few days to two weeks, depending on the specific situation and complexity of the project. By working on-site, visitors will have access to live experimental setups on which they will be able to test their software. Furthermore, the XIA software team will be available to provide assistance and help immediately without the limitations of either email or phone.

For situations where more time is required, additional hours of support may be purchased at XIA's standard consulting rate.

This program supports both our Handel and Xerxes driver libraries as well as custom driver development. Please contact XIA to determine which driver library is right for your application ([email protected]).

3/18/2010 8




2 USB and RS232 RDK Hardware Setup

2.1 MicroDXP and MicroComU Hardware Settings • All power and communications to the microDXP are carried via board-

to-board mating connectors on the microDXP and MicroComU boards. Note: Please refer to the hardware specifications in the separate MicroComU Technical Reference Manual for more detailed drawings, including connector locations, part numbers, switch settings, and power requirements.

• There are no jumpers to set on the MicroComU board. • There are DIP switches on the MicroComU board, but these only need

to be changed to support external I2C peripherals. See the MicroComU Technical Reference Manual as needed.

2.1.1 Power Supply Setting The MicroComU board requires that the attached microDXP board use

its on-board LDO regulators. However, this is the default configuration for microDXP boards.

Figure 2.1: Rapid Development Kit in USB Mode: connection diagram shows how to connect the

MicroComU and microDXP boards. The system may also draw power from the USB port itself. In this case, the AC wall adapter and connection to J10 may be omitted. Note that the J9, SW3, and J10 components shown are actually on the underside of the MicroComU companion board. The microDXP preamplifier-type selection switch is also shown.

3/18/2010 9


Figure 2.2: Rapid Development Kit in RS232 Mode: connection diagram shows how to connect the MicroComU and microDXP boards. The custom RS232 cable (part number CAB-DB9-3POS) should run between J2 on the MicroComU and a free COM port on the host computer (or a USB to serial port converter). Note that the J2, SW3, and J10 components shown are actually on the underside of the MicroComU companion board. The microDXP preamplifier-type selection switch is also shown.

2.1.2 Preamplifier Type Selection The only hardware setting on the microDXP board is the preamplifier

type selector switch. The location of the miniature two-position slide switch S1 is displayed in Figure A.1 of Appendix A. The two positions are silkscreen-labeled RAMP and OFFSET. Select RAMP for reset-type preamplifiers. Select OFFSET for RC-feedback preamplifiers.

2.1.3 Input Signal Attenuation The voltage range of the preamplifier signal must not exceed the input

range of the microDXP, excluding reset transients that exceed the range for a few microseconds. The input range is specified below in Table 2.1. To accommodate preamplifiers with an output range in excess of 4 Volts, an optional attenuation setting was included in the Revision C and later microDXP input circuitry. Attenuation and the increased input range are achieved by shorting with solder the two oval pads of R87 together. By default RC-type microDXP’s are shipped with the solder short omitted; reset-type microDXP’s are shipped with the solder short present.

MicroDXP Board Rev.

Input Range - 0dB Atten. (default - R87 clean)

Input Range - Attenuated (R87 solder-short present)

B +/- 5.7 V N/A (R87 not included) C +/- 3.9 V +/- 7.8 V

D, E +/- 3.9 V +/- 6.0 V Table 2.1: The microDXP analog input range depends on the board revision

and attenuation setting.

3/18/2010 10


1. Making Connections Make sure the MicroComU master power switch is switched off (SW3

lever up (toward circuit board) off before making connections. Alternatively, unplug both the power cable and the USB cable.

2.1.4 MicroComU to microDXP Connection The MicroComU and microDXP boards mate together using board-to-

board connectors. The MicroComU board ships with short machine screws loosely installed in the steel standoffs used to space the two boards. Remove but do not lose these screws. Next, ensure that the microDXP is in the correct rotation relative to the MicroComU board (see Figure 2.1 above). Sight through the mounting holes to make sure the two boards are aligned. Then gently press the microDXP down onto the MicroComU companion board. It should seat neatly against the steel standoffs. Finally, re-install the 4 machine screws to retain the microDXP board. Tighten (but do not over-tighten) with a Phillips screwdriver.

2.1.5 USB Attach the provided USB cable to a free USB port (preferably a USB

2.0 capable port) on the host computer. If needed for the application, a USB hub may be used. A powered hub will permit the system to run off USB power, just as it may when plugged directly into the PC. Use of an unpowered USB hub will require the use of the AC power adapter.

2.1.6 Detector and Preamplifier Caution: The standard-assembly microDXP accepts a maximum input voltage range +/- 5V. If the output voltage of the preamplifier exceeds this range, the microDXP must be modified before connections are made. Please contact XIA to discuss non-standard input voltage ranges.

We encourage you to follow the installation instructions and precautions provided by the detector/preamplifier manufacturer before making power and bias connections to these components. An input BNC cable adapter is included in the USB Rapid Development Kit to allow connection to a standard preamplifier signal output. Plug the small beige connector on this adapter into the analog input of the microDXP. Connect the BNC end to the your preamp cable. The connection at the microDXP end is rather delicate—please take care not to stress this cable.

2.1.7 Power Connect the provided AC adapter into a 100VAC to 240VAC at 50Hz

or 60Hz AC mains socket. (This AC adapter is compatible with the AC power supply and the AC plug conventions in North America, Japan, UK, Europe, and Australia.) Plug the output into the MicroComU primary power connector at J10 (see Figure 2.1 above). The system can now be powered on using the SW3 master power switch.

In most cases, the MicroComU / microDXP board set may be powered from the USB port instead. If the USB cable is plugged directly into the PC or

3/18/2010 11


into a USB powered hub, it should be possible to operate off USB power alone. However, XIA LLC recommends using the AC power adapter for initial testing of the system. If everything works, then proceed to change over to USB power.

3/18/2010 12


3 Using the microManager 2.3 Software

The microManager application can be used to configure the microDXP, to perform diagnostics and to acquire and export energy spectra.

Some microDXP features have not yet been implemented in microManager. The omissions include: Multi-SCA acquisition modes and the power-down sleep modes.

3.1 Installation

MicroManager 2.3 operates on Windows 98/Me/NT/2000/XP machines. Updates to microManager are available online at:

Note: Check for firmware and software updates at: http://www.xia.com/microDXP.html


The update installation file is a ZIP archive, which can be “un-zipped” with WinZip or a similar program.

3.1.1 First Steps 1. Please close all applications that are currently running. 2. Insert the CD into the CD-ROM drive or, if your copy was delivered

electronically, double-click the setup.exe program. If the CD installation does not start immediately, follow the instructions in steps (3) and (4).

3. Click the Start button and select the Run command. 4. Type X:\Setup.exe and click [OK], where X is the letter of your

CD-ROM drive.

3.1.2 After Installation When the microManager installation is complete, a shortcut to the

application will be located on your desktop. A copy of Adobe Acrobat® or Adobe Acrobat Reader® is required to view the help files distributed with microManager. If you need to install Adobe Acrobat Reader®, please go to the Adobe website:

http://www.adobe.com/products/reader/

3.1.3 File Locations After installation, the microManager executable, by default, is located in:

C:\Program Files\xia\microManager 2.3

MicroManager supports firmware update and backup procedures via the XUP utility, as described in §2. The “XUP” subdirectory is used to store firmware update files of the form “firmware_name.xup”. It is located in:

C:\Program Files\xia\microManager 2.3\XUP

3/18/2010 13



Backup files of the form “backup_*.xup” are automatically generated every time firmware is updated via the XUP utility and stored in a user-defined folder. By default the location is:

C:\Program Files\xia\microManager 2.3\backups

Update notices to standard firmware will be posted online at:


The actual update files will be emailed to individual customers. If you have not received an email and suspect that an update may be available, please contact us at:

[email protected]

3.1.4 Support Note: Check for firmware and software updates at: http://www.xia.com/microDXP.html

XIA values all of the feedback it receives from customers. For any software release, this feedback is an important component of the development cycle and XIA looks to use this feedback to improve the software. All bug fixes and feature suggestions should be directed to the above email address. Please be sure to include as much information as possible when submitting a bug report. For further instructions please refer to §1.4.

3.2 Starting Up the First Time When you start the MicroManager 2.1 for the first time a few

configuration tasks must be executed.

3.2.1 USB / COM Port Configuration MicroManager must first determine to which USB or COM (RS-232

serial) port the MicroComU or microCOM board is connected. The port number can be set manually or can be detected automatically.

Figure 3.1: The USB / COM Port Configuration panel appears the first time microManager 2.3 is started.

3/18/2010 14


mailto:[email protected]?subject=microDXP%20Firmware%20Update%20Request


3.2.2 Firmware Auto-Update MicroManager 2.3 requires firmware that may not exist on your

microDXP hardware, specifically DSP code revision 1.06 or later. The first time MicroManager 2.3 is run with a board running older firmware, the software prompts the user to update the DSP code. Unless you are running customized DSP code, the new code can automatically be downloaded by simply pressing the 'Upgrade' button, then selecting 'No' when asked whether you are running special firmware. If you are running customized firmware, please select 'Yes' and contact XIA for a customized XUP update file.

Figure 3.2: The microManager Upgrade Wizard panel appears if microManager detects a microDXP board that contains older firmware that is incompatible with microManager 2.3.

Figure 3.3: Do not remove power, or otherwise disturb the hardware or software during the XUP download process!

3.3 A Quick Tour of microManager 2.3

3.3.1 Windows and Panels When you start the program, the MicroManager 2.3 main window

should be displayed as in Figure 3.4. Note that tabbed panels are used. In the following, an individual tab is referred to as a pane.

The Settings panel contains the default Acquisition settings, Detector settings and Advanced settings panes. The default Acquisition pane provides access to Peaking Time selection, and peaking-time-related (PARSET) and MCA format (GENSET) parameters. It is intended to be the primary interface for setup and optimization as well as data acquisition, and is referenced

3/18/2010 15


throughout §3.4 and §3.6. The Detector pane contains global (GLOBSET) settings related to the detector type and preamplifier characteristics. The Advanced pane contains advanced processor GLOBSET settings.

The Graphics panel contains the default MCA spectrum display, and diagnostic Baseline and ADC display panes. The MCA pane displays acquired energy spectrum data and run statistics. Global MCA metrics (e.g. input count rate, realtime, etc.) are displayed in the Statistics sub-panel. Statistics for user specified spectral regions of interest (e.g. ROI-selected peak mean and FWHM) are displayed in the ROI Controls panel. The Baseline pane displays the diagnostic baseline histogram and baseline history data. The ADC pane is an oscilloscope tool for viewing the raw ADC trace. Zooming and panning in all Graphics Panel panes (i.e. MCA, Baseline, and ADC windows) can be customized using the Display Controls in conjunction with mouse operations both on the axes and in the spectrum display area itself.

The Status Bar along the bottom contains information about the state of the hardware and software, and the hardware serial number. The status indicator at the lower left corner of the main window changes to yellow during RS-232 communications, green when Idle and red when an error has been detected.

Figure 3.4: The microManager 2.3 application displaying the settings, spectrum acquisition and ROI

analysis tools. Note that both the settings panel and graphical display panels are tabbed, with the default general acquisition settings and MCA displays selected, respectively.

3/18/2010 16


3.3.2 Apply, Undo and Save The microDXP hardware includes non-volatile memory for storing

firmware (DSP and FPGA code) and parameter settings. Firmware is altered only through the XUP update utility accessed through the Firmware menu. Parameters can be altered through the software in two ways: The user can directly edit, test and save individual parameters or a complete set of saved parameters can be loaded using the XUP utility.

GENSET and PARSET settings can first be changed in the operating memory of the DSP for testing purposes without altering the non-volatile memory. This is done by first changing an editable field in the Settings Panel, then pressing the [Apply] button. Note that the [Save] button subsequently displays in bold, indicating that parameters in DSP memory differ from those stored in non-volatile memory. Once the desired behavior has been verified the new settings can be saved to non-volatile memory such that they are subsequently automatically loaded. Simply press the [Save] button. Press the [Undo] button to revert to previous settings in the DSP's operating memory. Note that if a save operation occurred before the [Undo], the [Save] button must be pressed again to push the original settings back into non-volatile memory.

A complete set of parameters can be saved by selecting Create Master Parameter Set… from the Firmware menu. This generates an XUP file that can be stored to disk and retrieved at a later time. This XUP file can be useful for debugging: By analyzing the file, XIA engineers have access to all the internal settings that might be causing problems. This process is particularly useful when a number of identically configured boards are required: The user simply optimizes the first board, saves the parameter set to the XUP format, then loads that XUP file to the other boards by selecting Download… from the Firmware menu and selecting the file. See §2 for a more detailed discussion of the XUP utility.

3.3.3 Preview of the Setup Process The microDXP has been designed with ease-of-use in mind.

MicroManager should be used to first optimize Global settings and all the parameters associated with each PARSET and GENSET (see below). Henceforth, during normal use the client software application need only modify two parameters, the pointers PARSET and the GENSET, and of course display or export spectrum data.

The setup process consists of first configuring the detector preamplifier settings, creating up to five MCA presentations, and optimizing the parameters linked to each peaking time. Optimization of other parameters, described briefly in §3.7.4, is not typically necessary.

3.3.4 GLOBSETs, PARSETs and GENSETs The GLOBSET contains global settings including detector/preamplifier

settings, advanced processor settings, run control settings, power-down modes, and diagnostic control settings. There is only one GLOBSET—these settings are used for all peaking times and MCA formats. GLOBSET settings are accessed via the Detector and Advanced tabs of the Settings panel. Because

3/18/2010 17


these settings are global, changes are simultaneously applied and saved to nonvolatile memory via the [Apply And Save] button.

The GENSET controls the number of bins and granularity of the MCA spectrum, as well as the base analog gain (if applicable). Five GENSETs can be stored, allowing for five different optimized MCA formats.

The PARSET contains all peaking-time-dependent parameters, e.g. thresholds, sampling interval, etc. Selecting a new Peaking Time automatically loads the complete set of parameters stored for that peaking time. There is a one-to-one correspondence between Peaking Time and PARSET.

Up to three Peaking Time Ranges, each a unique FPGA configuration code (also called 'FiPPI decimation’s, or 'FiPPIs' for short, in XIA jargon), can be loaded into the microDXP. Each FiPPI includes five Peaking Times. Given at least one and up to three Peaking Time Ranges, at least five and as many as fifteen PARSETs are available.

To maintain energy calibration and proper triggering across every combination of PARSET and GENSET, each PARSET includes five sets of thresholds and fine gain trim; one for each GENSET.

3.4 Detector/Preamplifier Settings In this section we will set and verify a few global parameters related to

the detector type and preamplifier characteristics. The Settings panel provides access to all microDXP settings. The panel contains three tab-selected panes. First select the Detector pane (see Figure 3.5). MicroManager 2.3 automatically determines the preamplifier type based upon the DSP firmware installed in non-volatile memory. It is very important that the 'preamplifier-type' hardware switch on the microDXP also be set properly, i.e. in agreement with the firmware, as described in §2.1.2 above.

Note: Make sure the 'preamplifier-type' hardware switch is properly set as described in §2.1.2 above.

The Detector settings include the signal polarity. For reset-type preamplifiers, the reset delay interval, the period of time following the preamplifier reset during which data acquisition is disabled, is also included. For RC-feedback preamplifiers the RC decay constant is included.

Figure 3.5: The Settings panel, with the Detector pane displayed, for reset-type preamplifiers (left) or RC-feedback preamplifiers (right).

Select the ADC pane of the graphics panel to view the preamplifier signal at the microDXP’s ADC.

3.4.1 Viewing the Preamplifier Signal The Graphics panel contains three tab-selected panes. First select the

ADC pane (see Figure 3.6 below). The ADC pane of the graphics panel

3/18/2010 18


displays the analog-conditioned preamplifier signal at the microDXP’s ADC. Press the [Read ADC] button to refresh the display. The Sampling Interval field controls the time interval between individual points, thus larger values will result in a longer displayed period. The minimum value, for 8MHz, of 125ns results in a displayed period of approximately 1ms. A detailed discussion of the ADC pane diagnostics can be found in §3.8.1 through §3.8.6.

3.4.2 Setting the Polarity We recommend that you first review §3.8.1 for an introduction to the

ADC trace display pane. The microDXP’s digital filters expect positive x-ray pulse-steps, i.e. with a rising edge. If the displayed x-ray steps have a falling edge (as in Figure 3.6 above), the detector Polarity setting must be modified. If the displayed x-ray steps have a rising edge (as in Figure 3.7 below), the microDXP polarity setting is correct—proceed to the next section.

Note: A detailed discussion of the ADC trace display pane diagnostics, including the polarity determination, can be found in §3.8.1.

To change the Polarity setting simply select Positive (+) or Negative (-) from the drop-down list and press the [Apply] button to apply the new setting and store it to non-volatile memory. Now press the [Read ADC] button again to verify positive pulse-steps.

3.4.3 Setting the Reset Delay (Reset-Type Preamplifiers) At this point in the setup it is not appropriate to change the Reset Delay

setting, as the gain and threshold settings affect the Baseline History display that is used for diagnostic feedback. §3.8.10 contains an illustrated discussion of the preamplifier reset transients and how to properly set the Reset Interval.

Briefly, reset-preamplifiers produce a large corrective 'reset' step when the signal goes out of range. This reset transient varies for different preamplifiers, both in the duration and in other signal characteristics, e.g. charge-injection overshoot and settling time. Data acquisition should be disabled during the transient. If it is not, artifact events can be introduced into the spectrum and resolution can be degraded due to baseline non-linearity. The Reset Interval sets the duration after a preamplifier reset is detected during which data acquisition is disabled. If the transient duration is longer than the default ten microseconds, the setting should be modified.

Note: The Baseline acquisition and diagnostic tools are discussed in §3.8.7.

3.4.4 Setting the Decay Constant (RC-Feedback Preamplifiers) Note: The RC decay

constant can be measured using the diagnostic ADC trace display, described in §3.8.5.

If you can determine the RC decay constant τRC of your preamplifier from related documentation, or can measure it using an external scope, do so now. Otherwise, first review §3.8.5 for an illustrated procedure for measuring the RC decay-constant τRC of the preamplifier signal using the diagnostic ADC trace display.

The decay constant must be set properly to get the best energy resolution. The RC Decay Constant setting has a granularity 125ns, and a maximum setting of 8.19 milliseconds. Enter the RC Decay Constant in microseconds and press the [Apply] button to apply the new setting and store it to non-volatile memory.

3/18/2010 19


Figure 3.6: The ADC pane of the Graphics Panel, displaying a series of four x-ray pulses from an RC-feedback preamplifier. Note that the polarity setting is wrong and the gain is set too low: ADC quantization ‘noise’ in this case would limit the precision of the pulse-height measurement.

3.5 Preliminary MCA (GENSET) Settings The General Parameter Set or GENSET includes the base analog gain,

the number of MCA bins and bin granularity. Up to five complete GENSETs can be modified and stored such that five optimized MCA formats can automatically be retrieved simply by selecting the GENSET parameter. For now we simply want to prepare GENSET #0 with some basic settings.

We strongly recommend that users first set the Dynamic Range and decide upon the desired MCA settings before tuning the gain via the automated base gain calibration routine.

3.5.1 Analog Gain vs. Digital Attenuation The Base Gain setting refers to the digitally-controlled analog, i.e. pre-

digitization, gain. Given the finite input range of the ADC, excessively low or high gain settings can yield poor performance. Setting the gain too low will result in insufficient digitization of the electronic noise, and thus degraded energy resolution. Setting the gain too high will result in attenuation of the higher energy x-ray peaks and increased deadtime overall: A pulse that forces the ADC signal out-of-range cannot be processed. Pulses over 20% of the ADC input range, so called extended-range events, will be increasingly under-represented in the recorded pulse-height distribution. For reset-type preamplifiers this behavior is independent of the input count rate. For RC-feedback detectors the signal will go out-of-range more often at higher input rates and thus this consideration is less important at low rates. The presence of

3/18/2010 20


extended-range events will also produce an overall increase in dead time, and thus reduce the output count rate.

The bin number and granularity settings are essentially digital attenuation settings. As such, it is possible to digitally compensate for an excessively high or low analog gain setting with the resulting poor energy resolution and/or count-rate performance, but nonetheless achieve a calibrated energy spectrum. For this reason the Dynamic Range software setting was introduced. The software uses this setting to ensure the dynamic range of the input signal, i.e. of the detector, is properly scaled to the ADC's analog input range. Although it is possible to directly modify the base gain, we recommend using instead the Dynamic Range setting in combination with the automated calibration software routine. The exception to this rule is the preliminary setting described below for detectors with particularly low or high gain.

3.5.2 Preliminary Base Gain Setting Optimal energy resolution will be achieved only if the gain is scaled

such that the detector and preamplifier noise is digitized properly: If the noise is not well sampled in the first place, the averaging processes implemented in the digital filtering circuitry cannot do much to reduce it.

On the other hand, optimum count-rate performance will be achieved only if maximum pulse-heights are scaled below 20% of the ADC range. For best results the gain should be set sufficiently high such that the preamplifier noise spans several ADC steps (i.e. if the noise is fully contained in one step, no amount of averaging will reduce the measured noise). Technically speaking, because only the 10 high order bits out of the 12-bit ADC waveform are displayed, one unit in the display corresponds to 4 units at the ADC output / digital-filter-input.

The default gain and threshold settings are conservative such that data can be immediately acquired with most detectors, however, if the ADC trace captured above does not satisfy the loose constraints described, adjust the Base Gain field in the GENSET section of the Acquisition pane and press [Apply]. Press the [Read ADC] button in the ADC trace display pane to view the result. Repeat until the target step-size and noise levels are achieved.

Note: Only the high-order 10-bits are displayed of the 12-bits digitized by the ADC.

3/18/2010 21


Figure 3.7: An ADC trace displayed with the correct polarity and acceptable gain. Note that the x-ray steps have a rising edge and are under 200 vertical units in height, and that the detector and preamplifier noise has indeed been sufficiently digitized.

3.5.3 Setting the Dynamic Range Now click on the Acquisition tab of the Settings panel. The Dynamic

Range setting at the bottom of the Acquisition pane refers to the dynamic range of the analog input signal, i.e. the detector and preamplifier, and not necessarily the energy range of the displayed spectrum. It is important to properly set this software parameter before attempting to calibrate the gain. First determine the dynamic range in electron-Volts of the detector/preamplifier. The typical x-ray dynamic range is 40keV to 80keV, though some thin-window detectors intended for soft x-rays may work best with the minimum 20keV dynamic range setting. Setting the dynamic range too high results in insufficient analog gain, and can cause degraded energy resolution. Setting the dynamic range too low results in excessively high analog gain. To the extent that this results in the signal going out of range, deadtime is increased.

3.5.4 MCA Settings Note: It is important to first set the Detector Dynamic Range (see § 3.5.3 above) before changing the gain and/or MCA settings.

The self-explanatory Number MCA Bins ranges up to 8192. A separate Bin Granularity setting determines the hardware (DSP) scaling factor, with four standard settings and a custom setting. These parameters must satisfy dynamic range constraints imposed by the digital filter pipeline, thus there are limits on the combinations of Number MCA Bins and Bin Granularity as outlined in Table 3.1. Using a larger-than-recommended number of bins for a given granularity will result in extended-range events—if such x-rays (see §3.5.1 above) are present—being displayed. If including more bins than the absolute maximum, the spectrum will include a high-energy dead region, i.e. there is no possibility of getting counts in this region. Also, keep in mind that the spectrum readout time is directly related to the number of bins.

3/18/2010 22


Recommended # MCA Bins

Absolute MAX # MCA Bins

Bin Granularity Scale Factor Bin Size

4096 8192 Very fine 1 2048 8192 Fine 2 1024 4096 Medium 4 512 2048 Coarse 8

< 512 (e.g. 128)

- Custom

(Bin Size) (e.g. 32)

Table 3.1: Suggested Bin Granularity settings based upon the Number of MCA Bins.

First select the desired Number of MCA Bins, and then set the Bin Granularity to the corresponding setting indicated in the table, or a finer to zoom in. Press [Apply], and then press [Save]. Note: Up to 8192 bins can be selected, though numbers greater than 4096 will always include extended range events. For this reason we don’t recommend starting out with more than 4096 bins.

3.6 Spectrum Acquisition At this point the pulse polarity and approximate gain should have been

verified using the diagnostic ADC trace display as described in section §3.4, and the dynamic range, number of MCA bins and bin granularity should be set as described in section §3.5 above.

Select the MCA tab of the Graphic Display panel to acquire energy spectra.

Now click on the MCA tab of the Graphic Display panel. The MCA pane displays the distribution of measured pulse-heights and thus, after calibration, the energy spectrum of the incident photons. Press the [Start] button to begin a data acquisition run. If the Continuous checkbox is selected the display will refresh automatically, otherwise data will only be displayed after the [Update] button is pressed and/or after the run is stopped.

An uncalibrated pulse-height distribution should now be displayed. Press [Stop Run] to end the spectrum acquisition run. A noise peak near channel zero (0) might be displayed, as in Figure 3.8, if the gain is set too high or a threshold is set too low. If the noise peak overwhelms the energy peak, or if no data is displayed it is likely that the polarity and/or approximate base gain has not been set properly—please review §§3.4 and 3.5 above before continuing.

3/18/2010 23


Figure 3.8: A 2048-channel pulse-height distribution (an uncalibrated Fe55 Kα/Kβ spectrum—the main peak should be at 5.9keV) viewed with a linear vertical scale.

3.6.1 ROI Selection In order to calibrate the bin scaling we must first designate the

calibration peak with a Region of Interest (ROI). By default the ROI table should display as in Figure 3.9a. Up to sixteen (16) ROIs can be added, with peak energy, FWHM and total counts displayed for each. Note: The energy resolution depends heavily on the Peaking Time (i.e. the selected Peaking Time may not produce optimal resolution).

1. Right-click in the spectrum display of the MCA Spectrum window area and select Place Cursor 1. Use the left mouse button to drag the cursor within the desired peak, zooming in if necessary using the mouse shift-click + drag operation. Note: Right-click and select Full Scale to display all data.

2. Now right-click on Cursor 1 and select Auto ROI. A shaded region of interest should appear within the peak. If the number of counts in the peak is insufficient, the Auto ROI function will not adequately select the peak. Note: If necessary, the ROI limits can be adjusted directly using the left-mouse click-and-drag operation, or by editing the Lower and Upper fields in the ROI table. The ROI table should now display as in Figure 3.9b. Note: The

software will scale the active ROI (denoted by an ACT in the far-left column of the ROI table) to the calibration energy. The color and visibility of each ROI can be changed by clicking in the ‘C’ and ‘V’ columns, respectively. ROIs can be locked by clicking in the ‘L’ column.

3/18/2010 24


3.6.2 Base Gain Calibration Note: For the base gain calibration make sure that Calibrate Gain is selected under the Gain menu.

Now we are ready to calibrate the base gain, the gain value stored in the GENSET. Make sure that Calibrate Base Gain is selected under the Gain menu. Enter the energy of selected peak in the Calib. (keV) field of the ROI table, and press the [Calibrate Gain] button to automatically adjust the Base Gain. Press the [Start Run] button to acquire more data. Note that the peak should now be calibrated as in Figure 3.10, and the Gau-Mean field in the ROI table should roughly match the calibration energy entered as in Figure 3.9C.

The total gain is a combination of the base gain and, if non-zero, the fine gain trim value that is stored on per-peaking-time basis, i.e. in the PARSET. It is not important point to achieve a perfect Base Gain calibration—fine gain trim on a per-peaking-time basis is intended for this purpose, as described in §3.7.2.

A)

B)

C)

Figure 3.9: A) default ROI table, B) with an uncalibrated peak selected, and C) after base gain calibration of a 5.9 keV Fe55 Kα peak.

Figure 3.10: The Fe55 Kα peak is now displayed properly at 5.9keV.

3/18/2010 25


3.7 Peaking Time (PARSET) Optimization For each Peaking Time the DSP stores a complete set of all related

spectrometer parameters into non-volatile memory. The parameter sets (PARSETs) are first optimized by the user and then saved to the on-board non-volatile memory. Five Peaking Times are available for each Peaking Time Range (FiPPI file) purchased. Up to three Peaking Time Ranges can be stored simultaneously, yielding a maximum of fifteen (15) independently optimized Peaking Times. Re-selecting an optimized Peaking Time retrieves all relevant digital filtering and peak inspection parameters (e.g. gap time, thresholds, pileup inspection interval, etc.). This functionality is particularly useful in embedded systems: The configuration and optimization procedures can be delegated to the MicroComU or microCOM board and microManager software, leaving a very small data acquisition command set for the embedded system itself. The configuration process need only be performed once, though of course the parameter sets can later be modified.

Peaking Time (PARSET) selection and the most often used parameter settings are accessed directly from the Acquisition pane of the Settings panel. Less often used parameters can be accessed by pressing the [Edit Filter Parameters] button. For each FiPPI decimation stored in the nonvolatile memory, there will be a corresponding Peaking Time Range displayed in the PARSET pane. Simply select the desired range using the Peaking Time Range drop-down menu, and the Peaking Time drop-down list is refreshed with new values that can then be selected. To expedite the setup process, we suggest starting with the longest Peaking Time within a given Peaking Time Range.

Figure 3.11: The Acquisition pane. Peaking time and threshold selection and storage to nonvolatile memory are executed with this tool.

First select the desired FiPPI decimation from the Peaking Time Range drop-down list. Next, select the desired Peaking Time from the drop-down list. It is NOT necessary to press [Apply] when making these selections. The following sections describe the process of selecting and storing the individual parameters for one peaking time.

3/18/2010 26


Note: Please refer to the microDXP Technical Reference Manual for a condensed summary of the RS-232 command and response protocol. Users who wish to develop the configuration routines into their software should refer to the RS-232 Command Specification (a separate document) for a detailed presentation of all RS-232 commands. microDXP-related documents are available online at:


3.7.1 Threshold Settings To modify thresholds in the Acquisition Values panel:

Modify the threshold(s).

Press [Apply]

The thresholds are typically the most important PARSET settings to get right. Depending on the preamplifier type and firmware purchased, up to three thresholds, each with its own balance of temporal vs. noise performance, can be used simultaneously: The fast-filter Trigger threshold achieves the best pulse-pileup rejection, whereas the slow-filter Energy threshold achieves the best noise rejection. The intermediate-filter Baseline threshold is somewhere in the middle. Thresholds, if available, can be individually disabled by checking the adjacent checkbox. The Energy threshold can also be disabled by setting it to zero.

By default the thresholds are set conservatively, however, the best performance will be achieved when the thresholds are set just above the noise as described below. We strongly recommend saving the PARSET after each threshold is verified, by pressing the [Save] button.

3.7.1.1 Disabling the Slow Threshold Note: Only use the Energy Threshold for soft x-ray work at low count rates.

The Energy Threshold should be disabled in nearly all cases. Although its excellent noise reduction also allows detection of the very lowest energy x-rays, its slow response precludes an accurate determination of deadtime. This results in both degraded pulse pileup inspection and an error in the input count rate calculation. The Energy threshold should thus be used only at low count rates, where pulse-pileups seldom occur.

By default the Energy Threshold should be factory-set to zero (0), which disables the threshold. If this is not the case, edit the value and press [Apply].

3.7.1.2 Setting the Baseline Threshold (Reset Preamplifiers Only)

Please refer to the §3.8.7 for a brief discussion of baseline acquisition, or refer to the microDXP Technical Reference Manual for further details.

1. Disable the Fast Threshold by checking the adjacent checkbox and pressing [Apply].

2. By default the Baseline Threshold should be set to the maximum value, 255. Typically this value can be set much lower: in nearly all cases a starting value of 60 is more appropriate. Edit the value and press [Apply].

3. [Start] a run and [Update] the display in the MCA pane such that spectrum data is displayed. [Stop] the run.

4. If the noise peak is NOT displayed, reduce the Baseline Threshold and repeat. If the noise peak IS displayed, increase the Baseline Threshold and repeat until the noise peak is eliminated.

3/18/2010 27



5. Re-enable the Fast Threshold by checking the adjacent checkbox and pressing [Apply], then press the [Save] button to save the new Baseline Threshold to the current PARSET.

3.7.1.3 Setting the Fast Threshold

The Energy Threshold should be set to zero (0), and the Baseline Threshold should be set properly. If this is not the case, please review the previous sections.

1. Disable the Baseline Threshold by checking the adjacent checkbox and pressing [Apply].

2. By default the Fast Threshold should be set 48. If this is not the case, edit the value and press [Apply].

3. [Start] a run and [Update] the display in the MCA pane such that spectrum data is displayed. [Stop] the run.

4. If the noise peak is NOT displayed, reduce the Fast Threshold and repeat. If the noise peak IS displayed, increase the Fast Threshold (now in very smaller decrements) and repeat until the noise peak is eliminated.

5. Re-enable the Baseline Threshold by checking the adjacent checkbox and pressing [Apply], then press the [Save] button to save the new Fast Threshold to the current PARSET.

Note: If the gain is subsequently changed, the thresholds will have to be updated and the PARSET saved again.

3.7.2 Fine Gain Trim Note: The fine gain trim value is stored on a per-peaking-time basis, i.e. in the PARSET.

Now we are ready to trim the gain for this peaking time. Remember, the base gain value was stored in the GENSET. The fine gain trim, or per-peaking-time calibration, is stored in the PARSET. In fact there is a Fine Gain Trim value stored for every PARSET/GENSET combination, allowing for calibrated data acquisition at all settings.

1. Select Calibrate Gain Trim under the Gain menu. 2. Enter the energy of selected peak in the Calib. (keV) field of the ROI

table. Make sure the selected ROI is Active (click in the far left field of the ROI table such that the text "ACT" appears)

3. Press the [Calibrate Gain] button to automatically adjust the Fine Gain Trim.

4. Press the [Start Run] button to acquire more data. Compare the measured mean energy in the Gau-Mean field in the ROI table to the calibration energy entered. Repeat step 3 until the fields match to the required precision.

5. Press the [Save] button to save the Fine Gain Trim to the current PARSET.

3.7.3 Optimization of Remaining PARSETs You’re now ready to repeat the above process for each of the other four

PARSETS of the selected FiPPI, saving each one after the thresholds have been set and verified. The expedited procedure is outlined below:

1. Write down the Fast Threshold and Baseline Threshold settings for your optimized PARSET.

2. Select the next Peaking Time from the drop-down list.

3/18/2010 28


3. Set the Fast Threshold and Baseline Threshold to the values from step #1 above and press [Apply].

4. Don’t re-optimize the Fast Threshold—the same value should be used in all PARSETs.

5. If, as initially recommended, you are changing from a longer Peaking Time to a shorter one, the Baseline Threshold will now be set just a little too high. Optimize the Baseline Threshold as described in §3.7.1.2.

6. Calibrate the Fine Gain Trim as described in §3.7.2. 7. Repeat steps 1-6 (steps 1-3 for decimation 0) above for each remaining

Peaking Time. 8. If more than one FiPPI is included in your firmware, select the next

Peaking Time Range and again repeat for each of the five PARSETS. Again, start with the longest Peaking Time.

Congratulations! You’ve just completed the basic configuration and

optimization and are ready to take some real data. We’ve attempted to provide enough software features and documentation to characterize the microDXP performance with a given detector at a basic level, i.e. map the resolution vs. peaking time. If you do not achieve the expected performance after following the above procedure, continue reading §3.7.4 below: Further PARSET optimizations are described briefly below:

• Adjusting the slow gap time for longer preamplifier risetimes is described in §3.7.4.1

• Peak sampling at short peaking times may need adjustment, as described in §3.7.4.2

• Adjustment of the pileup inspection parameters is described in §3.7.4.3.

3/18/2010 29


Figure 3.12: A calibrated Fe55 spectrum viewed with a logarithmic vertical scale. An ROI has been created and calibration energy entered, and thus the horizontal axis of the MCA and the measured centroid and FWHM have been scaled.

3.7.4 Advanced Optimizations Note: Explanations of the digital filtering algorithms are described in

detail in the microDXP Technical Reference Manual. Open the Filter Parameters panel by pressing the [Edit Filter

Parameters] button in the PARSET area of the Acquisition pane. This panel displays the parameters that control the digital filtering algorithm.

3/18/2010 30


To open the Filter Parameters panel, press the [Edit Filter Parameters] button in the Acquisition pane

Figure 3.13: The Filter Parameters panel displays the parameter settings for the current Peaking Time.

Changing any of these parameters can significantly change the performance of microDXP at the selected Peaking Time.

1. Make sure the desired Peaking Time is selected from the drop-down list.

2. Press [Edit Filter Parameters] to open the Filter Parameters panel. 3. Edit the parameters of interest (e.g. Slow Gap, Peak Interval, Peak

Sample, Fast Length, Fast Gap, Max. Width). 4. Press [OK] to apply the changes to operating DSP memory for testing. 5. Acquire data and verify improved performance. 6. [Save] the PARSET to store the modified parameters to non-volatile

memory such that they will be retrieved the next time the Peaking Time is selected.

All FiPPI decimations D employ an energy filter controlled by the

parameters SLOWLEN, SLOWGAP and PEAKINT. SLOWLEN is the interval of time, in units of decimated clock cycles, during which the decimated ADC signal is integrated, referred to as the peaking time.

3.7.4.1 Preamplifier Risetime: SLOWGAP

SLOWGAP is the gap time, visible as the ‘flat-top’ region of the trapezoid. Subject to the restriction that it must exceed 3, SLOWGAP is set such that the flat-top interval is longer than the risetime of the preamplifier output pulses by at least 1 decimation period:

Gap Time = (2 D * SLOWGAP * 125ns) > pulse risetime+ 2D * 125ns or: (2 D * (SLOWGAP-1) * 125ns) > pulse risetime

Equation 3-1

3/18/2010 31


...Where an 8MHz pipeline clock speed is assumed. If 16MHz is used, “125ns” should be replaced with “62.5ns”. Note: If the input signal displays a range of risetimes (as in the “ballistic deficit” phenomenon) the slow filter gap time should typically be extended to accommodate the longest risetime in the range.

PEAKINT sets the deadtime in the energy filter and is thus a primary pileup inspection parameter, as discussed in §3.7.4.3 below. If the SLOWGAP is modified, however, PEAKINT should be incremented or decremented by the same amount. It is set by default to:

PEAKINT = SLOWLEN + SLOWGAP

Open the Acquisition Values panel and press GEN/PAR Viewer. Remember that individual SLOWGAP and PEAKINT settings are stored and retrieved for each Peaking Time. Edit SLOWGAP as necessary, making sure to increment/decrement PEAKINT by the same amount, and press [Save PARSET].

3.7.4.2 Peak Sampling in Decimation 0 FiPPIs: PEAKSAM

FiPPI

Decimation #ADC codes pre-averaged

Peaking times available

with 8MHz clock

Peaking times available

with 16MHz clock 0 0 0.75, 1.125, 1.5,

2.25, 3 0.375, 0.5625, 0.75,

1.125, 1.5 Table 3.2: The Peaking Time ranges for decimation 0, by clock speed option.

The decimation 0 FiPPI is somewhat of a special case because the digital filter pipeline runs at the full ADC clock rate. Although the very highest count rates are achieved using the decimation 0 FiPPI, triggering, sampling and baseline acquisition are somewhat compromised. As a result there are two primary differences in the implementation that must be emphasized:

No intermediate baseline filter exists for decimation 0. Instead the energy filter is sampled whenever sufficient periods of inactivity in the fast filter indicate no x-ray energy is present. Thus, the baseline threshold is not available for decimation 0.

The peak-sampling algorithm runs on a fixed timing model—the peak is sampled a fixed time after the threshold is crossed. Other decimations use a peak-finding algorithm—the peak value within a pre-defined interval is selected.

The parameter PEAKSAM must be set properly in order to achieve a spectrum. Briefly, allowable values range from the slow filter length SLOWLEN, the successive peak interval PEAKINT:

SLOWLEN ≤ PEAKSAM ≤ SLOWLEN + SLOWGAP

This value of PEAKSAM is set by default to SLOWLEN + 1, but may need to be optimized empirically by the user. Please refer to the Peak Sampling vs. Peak Finding section in the microDXP Technical Reference Manual for further details, or contact XIA directly if you are having trouble acquiring a spectrum using the decimation 0 FiPPI.

Press the Edit Filter Parameters to open the Filter Parameters panel. Edit Peak Sample as necessary and press [OK]. Remember that individual settings are stored and retrieved for each Peaking Time.

3/18/2010 32


3.7.4.3 Pileup Inspection: MAXWIDTH, PEAKINT

Undetected pulse-pileup results in unwanted pileup peaks in the spectrum. Pileup peaks in the spectrum can easily be identified by noting that the apparent energy of the pileup peak is exactly twice (or three times, etc…) the energy of its associated real x-ray peak.

Two pileup inspection methods are utilized in the microDXP. Fast inspection monitors the pulse width of the fast filter output, or more specifically, the time during which the fast threshold is exceeded. Slow inspection monitors the time between two successive fast filter threshold crossings.

The fast filter is controlled by the parameters FASTLEN and FASTGAP, which are functionally equivalent to the slow filter parameters described in the previous sections, but which run at the pipeline clock speed (i.e. NOT decimated). Note: It is not necessary to set the FASTGAP in relation to the preamplifier risetime, in fact it is set to zero (0) by default, and should left so in nearly all cases.

For an infinitely short preamplifier risetime, the fast filter produces a trapezoid of maximum width:

Maximum width = SLOWGAP + 2*SLOWLEN

The parameter MAXWIDTH sets the width limit for acceptable events, in units of the pipeline clock interval (i.e. 125ns for 8MHz, 62.5ns for 16MHz). The fast filter trapezoidal waveform convolutes the preamplifier risetime tR and thus MAXWIDTH should be increased accordingly:

MAXWIDTH = SLOWGAP + 2*SLOWLEN + (tR / 125ns)

The default values (MAXWIDTH = 12; FASTLEN = 4; FASTGAP = 0) is thus appropriate for a preamplifier risetime no greater than 500 ns. Note: “125ns” in the equation should be replaced with “62.5ns” if the pipeline clock runs at 16MHz.

Slow inspection monitors the time between two successive fast filter pulses. PEAKINT sets the minimum separation, expressed in units of the decimated clock. It is set by default to:

PEAKINT = SLOWLEN + SLOWGAP

...and should be left so in nearly all cases. Smaller settings will increase the magnitude of pileup peaks. Longer settings may in some cases improve pileup rejection. In most cases it will have no effect on pileup but will always increase the dead-time-per-event and thus reduce throughput.

Press the Edit Filter Parameters to open the Filter Parameters panel. Edit Max Width and Peak Interval as necessary and press [OK]. Start a new run and re-examine the ratio of the identified pileup peak to its associated energy peak. Remember that individual settings are stored and retrieved for each Peaking Time.

3.7.5 Viewing the run statistics The run statistics are displayed in the upper right corner of the MCA

panel. Real time and live time are displayed in seconds; input count rate and output count rate are displayed in kilo-counts-per-second. The total number of events in the spectrum is also displayed.

3/18/2010 33


3.7.6 Saving a spectrum The spectrum export function produces a text file with a descriptive

header and a list of values, the counts in each bin. The energy-per-bin and run statistics are included in the header. To save a spectrum, either press the [Save Spectrum] button or select Save Spectrum… from the File menu. You will be prompted to enter the file name and select a location to save the file.

3.8 Diagnostics

3.8.1 Board Information The Board Info panel is used to display basic information about the

configuration and status of the microDXP hardware. Open the panel by selecting Board Info… under the View menu.

Figure 3.14: The Board Information panel, displaying the hardware configuration information.

Press the [Read Status] button to display the current status of the PIC microprocessor and DSP. If no error conditions have been detected all values should read zero. Press the [Read History] button to display a history of firmware updates loaded to non-volatile memory. Press the [Read Information] button to display the current hardware and firmware configuration, as displayed in Figure 3.14 above. Finally, press the [Export to File…] button to store all info, i.e. status, history and configuration information,

3/18/2010 34


to a text file. This text file is critical to XIA engineers when attempting to diagnose hardware and/or firmware problems.

3.8.2 Handel Log File The Handel log file is accessed by selecting Handel Log… under the

View menu. This log is automatically saved to:

~\microManager 2.3\micromanager.log

The log file can be helpful to XIA engineers when attempting to diagnose hardware and/or firmware problems.

3.8.3 The ADC Trace Panel The ADC trace panel displays 8,000 points of the digitized preamplifier

signal and can be used as a diagnostic tool during setup and debugging. The Trace Wait Time field controls the time interval between individual points. The minimum value or 125ns results in a displayed period of approximately 1ms. Note: Only the top 10 bits of the 12-bit ADC waveform are displayed vs. time, producing a full vertical scale of 0 to 1,024. Thus 1% of the ADC range is roughly 10 vertical units.

Note: Only the high-order 10-bits are displayed of the 12-bits digitized by the ADC.

Typically, the signal polarity and the rough gain are determined by examining raw preamplifier pulses in this window. This diagnostic panel is also useful for tracking down noise and electromagnetic interference (EMI). Open the panel and press the [Read ADC] button to refresh the display. Before setting the signal polarity and gain, we must first identify x-ray pulses in the display. Once the x-ray steps have been identified, we can empirically set the polarity, gain and thresholds, described in §3.4.

3.8.4 Identifying Noise It is important to identify the noise component of the signal. An ADC

trace displaying only noise is shown in Figure 3.15. In this case a significant low-frequency noise component (i.e. in the 100Hz -1kHz range) is displayed, in addition to high-frequency noise. It is important to make the distinction between high and low-frequency noise. The determination depends on the spectrometer filter length (i.e. slow filter peaking time) relative to the period of the noise component: Noise components with a period much greater than the peaking time are referred to as ‘low-frequency’, are reduced through baseline averaging; those with a period much shorter are referred to as ‘high-frequency’, and are reduced through integration in the energy filter itself. Generally speaking ‘mid-frequency’ noise, that is, components with a period similar to the filter length, is the most difficult to deal with.

3/18/2010 35


Figure 3.15: An ADC trace displaying noise from a reset-type preamplifier. Trace Wait is set to 1 μs, thus the 8000 point display spans 8 ms.

3.8.5 Measuring the RC Decay Constant (RC Preamplifiers ONLY) The ADC Trace panel is also useful for measuring the decay time for

RC-feedback preamplifiers. 1. First acquire an ADC trace that includes at least one well separated x-

ray event as in Figure 3.16 below. 2. Use the zoom tool (accessed via the right click menu or through the

display controls at the graph’s upper left) if necessary to expand the horizontal axis about the selected event such that the entire decay time is displayed.

3. Place Cursor 1, by right-clicking in the display area and selecting “Place Cursor 1”, at the peak value of the x-ray pulse. Similarly, place Cursor 2 immediately before the x-ray pulse such that a baseline value is selected, as in Figure 3.16.

4. Record the dY value from the cursor data display—this is the pulse height.

5. Now move Cursor 1 to the point on the decay curve that produces a new dY value that is 1/e times the measured pulse height:

dY’ = (1/e) · dY ~ 0.36 · dY

6. The cursors should now be separated by the time constant τ, displayed in μs in the dX field, as in Figure 3.17 below.

3/18/2010 36


Figure 3.16: A well separated event with an amplitude of ~ 91 vertical units.

Figure 3.17: The RC decay time of the previous figure is measured to be 49.75 microseconds.

3/18/2010 37


3.8.6 Tracking Steps (Reset-Type Preamplifiers ONLY) For reset-type preamplifiers additional signal transients are present due

to the microDXP itself. The Analog Signal Conditioner (ASC) dynamically maintains the signal within the ADC input range by introducing large voltage steps of approximately one half the ADC range (i.e. pushing the signal from the ADC boundary to near mid-range). The result is a tracking step waveform, which is qualitatively similar to the step produced by an x-ray. Tracking steps can be identified by noting that the transients originate near the ADC minimum (0) or maximum (1024) and terminate near mid-range (512 ± 200). The ADC trace display is somewhat misleading regarding such out-of-range events: ADC trace acquisition to memory is halted until the signal is back in-range, so that the out-of-range interval is omitted from the display. As a result it may not appear that the signal actually went out-of-range. Note: The ADC signal is most often pushed out-of-range by an x-ray step, though it may also be driven out of range by the preamplifier resetting mechanism. At low rates it may just drift out on its own (as occurs in Figure 3.18).

Two tracking steps are displayed in Figure 3.18. Note that the individual x-ray steps are in the range 20 – 100 vertical units, which is approximately 2% - 10% of the ADC input range. We frequently refer to x-ray step heights in terms of ADC percentages. Note: Figure 3.18 indicates a fairly low input count rate (roughly 1.5 kcps).

Figure 3.18: There are approximately 120 x-rays displayed for a reset-type detector. The two tracking steps are introduced by the microDXP analog signal conditioner (ASC) in response to the signal drifting out of range low. Given the 80ms time scale, the input count rate (as best we can determine) is ~ 1,500 counts per second.

3/18/2010 38


3.8.7 Baseline Acquisition Select Diagnostics » Baseline Histogram... to view the distribution of instantaneous baseline samples. Select Diagnostics » Baseline History... to view the computed average of baseline samples as a function of time..

Understanding Baseline acquisition and averaging is critical to optimizing the microDXP’s performance. The Baseline is simply the response of the digital filters when no photons are present. As is standard in pulse-processing applications, Baseline measurements are summed over a finite interval to generate an average value that tracks actual variations in the preamplifier output independent of incident photons. This average is subtracted from the instantaneous measurements of step-pulse heights, yielding the standard double-correlated improvement in noise.

Theoretically the distribution of baseline samples is Gaussian with a constant average value. Real world detectors and preamplifers generate several types of nonlinearities in the baseline distribution, and the mean value may wander with temperature, the rate of incident photons, etc. Reducing the number of samples in the average, or the Baseline Average Length, often is the best solution for a time-variant baseline. Nonlinearities correlated with the reset waveform, i.e. curvature in the response, can be remedied directly by increasing the detector Reset Delay setting, the period after each reset during which the microDXP disables data acquisition. A more extreme approach is to enable the 'baseline cut' routine under Advanced settings. This is a DSP routine that examine the baseline distribution, and simply exclude outliers from the running average. Procedures for setting each of these parameters are described briefly. Please refer to the microDXP Technical User Manual for a thorough discussion of baseline processing.

Baseline acquisition is controlled by the Baseline Threshold, the number of samples averaged, or Baseline Average Length, and the Reset Delay, the time interval after each preamplifier reset during which data acquisition is disabled. The baseline is displayed in two ways: The Baseline Histogram shows the distribution of instantaneous baseline measurements, ie. the noise peak. The Baseline History displays the computed average as a function of time. Both views are accessible within the Baseline graphic display pane.

3.8.8 The Baseline Threshold The Baseline Threshold has an 8-bit range that is factory set to the

maximum value of 255. This threshold is used both to acquire valid baseline samples and to trigger on x-ray events in the baseline, or intermediate filter. An aggressive setting can result in better sensitivity to low-energy x-rays. An overly-aggressive setting can halt baseline sampling and thus spectrum acquisition.

The user is instructed how to arrive at and store the proper setting (see §0). Note that the default setting provides little discrimination against events, thus the baseline histogram reflects samplings of the photon energy distribution as well as the noise peak (see Figure 3.19). Nonetheless at low to moderate event rates the vast majority of the measurements still fall on the noise peak as intended, and the baseline average is still largely functional. At higher rates the average will be increasingly corrupted by the growing energy component in the average, resulting in a rate-dependent shift in measured event pulse-heights. This degradation disappears when the baseline threshold is set correctly.

3/18/2010 39


Figure 3.19 Baseline histogram acquired with an Fe55 source at moderate input count rate, and with the baseline threshold set to the maximum value of 255. The vertical axis is displayed on a logarithmic scale. Note the noise peak near bin -150, and the significant energy component to the right.

Figure 3.20: A very clean baseline histogram with the threshold set correctly—the noise peak is isolated and Gaussian in appearance.

The Baseline Histogram panel is a useful tool for checking the Baseline Threshold setting. Open the Baseline Histogram panel and press [Update] to refresh the display. To zoom in on the noise peak select Zoom

3/18/2010 40


from the left-most display control (located along the top-left of the panel) and drag within the histogram display. To pan, left-click and drag directly on the axes. If the Baseline Threshold is set too high, part of the energy spectrum may be displayed in the baseline distribution as in Figure 3.19 above. If the Baseline Threshold is set correctly, only the noise peak should be visible. For a high quality detector and preamplifier, the noise peak should resemble a symmetric Gaussian distribution as shown in Figure 3.20 above.

3.8.9 Number of Samples in the Baseline Average Any and all effects that result in a time-variant baseline can be

mitigated by reducing the number of samples averaged, or Baseline Average Length. The Baseline Average Length is part of the PARSET, and is thus stored on a per-peaking-time basis.

Open the Baseline display panel and press [Get Baseline History]. Each point in the display represents the averaged baseline at that instant. The number of baseline points included in the average is determined by the DSP parameter BLFILTER according to the following equation:

# Samples Averaged (Baseline Average Length) = (32,768 / BLFILTER)

The Baseline Average Length defaults to 128 for reset-type preamplifiers and 64 for RC-feedback preamplifiers. We have found this to be a good balance for most detectors over a range of peaking times. At very high rates, and alternatively for lower quality detectors with significant real variations in the baseline, it is best to reduce the Baseline Average Length. At shorter peaking times it is often advantageous to average more points because each individual point contains a larger noise component than for longer peaking times.

3/18/2010 41


Figure 3.21: A skewed baseline histogram (foreground) resulting from curvature in the preamplifier large signal response. Note the cycling in the baseline history trace (background)—this is essentially a plot of the preamplifier slope v. time, indicating dramatic variations in slope across the reset range.

Open the Acquisition settings panel, select desired Baseline Average Length from the drop-down list and press [Apply]. Press [Get Baseline History] in the Baseline pane to refresh the display. When the desired performance has been verified press [Save]. Remember that individual settings are stored and retrieved for each Peaking Time.

3.8.10 The Reset Interval It is fairly common to see some skew in the noise peak when working

with reset-preamplifiers, resulting from nonlinearities in the preamplifier large-signal response. The nonlinearity is typically most dramatic during, and in some cases confined to, a period of microseconds immediately following the reset. This condition can also be diagnosed using the Baseline History display, which reflects the periodic variation in the baseline average (see Figure 3.21). In extreme cases the nonlinearity is even visible as curvature in the ADC Trace. The Reset Interval (expressed in units of microseconds) determines the wait time after preamplifier resets during which the spectrometer is disabled. Many detectors will require more than the default 10μs to settle.

The Reset Interval setting can be modified in the PARSET section of the Acquisition settings pane. Enter the Reset Interval in microseconds and press the [Apply] button. Now press the [Get Baseline History] button again to verify that the periodic variation in the average has been reduced if not eliminated.

3/18/2010 42


Figure 3.22: A typical good baseline history trace.

3.8.11 The Baseline Cut As specified above, a DSP subroutine may be enabled to specifically

exclude outlier baseline samples, i.e. those that include real event energy, which can lead to peak shifting at high event rates. Please note that the baseline cut is not recommended for RC-feedback preamplifiers, and is not recommended in any case where the count-rate shifts dramatically during a data acquisition run.

The baseline cut is expressed as a fraction of the peak value of the baseline distribution; by default, the baseline cut is set to 5%. The cut values are based on the baseline histogram, and are recalculated every time the histogram overflows (every few seconds). The DSP searches on either side of the peak of the baseline distribution for the first bin whose contents are less than the cut (.05 by default) times the peak value; these bin numbers are used to calculate the actual baseline cut. The cut fraction is stored in the parameter BLCUT, expressed in 16-bit fixed-point notation. Interpreted as an integer,

BLCUT = (cut fraction)*2**15

The default 5% cut thus corresponds to BLCUT=1638 decimal (or 666 hex). The actual cut values determined by the DSP code are stored in BLMIN and BLMAX.

The Baseline Cut is enabled/disabled in the Advanced settings panel. Simply check or uncheck the "Enable baseline cut" checkbox and press the [Apply] button. Now press the [Update] button in the Baseline History panel to verify that the periodic variation in the average has been reduced if not eliminated. Note that this is a global setting, thus the baseline cut will be enabled for all peaking times.

3/18/2010 43


3.8.12 The DSP Parameters Panel All of the DSP parameters can be viewed directly through the

diagnostics panel. Open the DSP Parameters panel under the View menu. Note that the values can be displayed in hexadecimal or decimal by choosing from the drop-down list. Simply edit a field and press return to write a parameter to DSP memory.

Figure 3.23: The DSP Parameters panel, used for diagnostic purposes.

2. The XUP Utility The XUP file format is used for all microDXP firmware operations.

An XUP file can contain any combination of the following data:

• DSP program code • FiPPI (FPGA) configuration code • Parameter sets (i.e. PARSETs and GENSETs)

MicroManager supports firmware update and backup procedures via

the XUP utility. Three operations are supported, selected under the Firmware menu:

1. Create Master Parameter Set… Saves all parameter sets (Globals,

GENSETs and PARSETs) from the connected microDXP to a “Master Parameter Set” XUP file that can be downloaded to other boards.

2. Download… Downloads an XUP file—a firmware update or a Master Parameter Set—to the connected microDXP. A backup file is automatically generated whenever new firmware is downloaded.

3. Restore… Downloads a previously created firmware backup to the connected microDXP.

3/18/2010 44


The “XUP” subdirectory is used to store firmware updates and Master Parameter Sets of the form “firmware_name.xup” and automatically generated backup files of the form “00000x.bak”. It is located in:

~\microManager 2.3\XUP

Updates to standard firmware will be posted online at:


Custom update files will be emailed to customers. If you have not received an email and suspect that an update may be available, please contact us at:

[email protected]

3.8.13 Saving a Master Parameter Set The XUP utility supports the importing and exporting of parameter

sets, i.e. GENSETs and PARSETs. This makes it possible to identically configure a number of microDXP’s after a single unit has been optimized.

To export parameters, simply select Create Master Parameter Set… from the Firmware menu, choose a filename (e.g. “MasterSet1.xup”) and a directory and press [Save].

Warning! If the update procedure returns an error, simply close the XUP Update panel by pressing the ‘X’ in the upper right-hand corner, and try again. It is not necessary to restart the software or cycle the power.

3.8.14 Downloading an XUP or Backup File Standard XUP files will only load successfully if the following

requirements are satisfied:

• The pipeline clock speed of the XUP matches the pipeline clock speed already stored on the microDXP (i.e. the pipeline clock speed that was purchased).

• The number of peaking time ranges (i.e. FiPPI decimations) matches the number previously stored on the microDXP.

To download a firmware udpate, select Download... from the Firmware menu. Use the folder browse button to select the desired XUP file and press the [Download] button. A backup file is automatically generated whenever new firmware is downloaded. To restore the microDXP to a previous state, select Restore… from the Firmware menu, select the appropriate XUP file (search by date if necessary) and press the [Download] button.

Figure 3.24 Do not disturb the software or hardware during the XUP download process!

3/18/2010 45


mailto:[email protected]?subject=microDXP%20Firmware%20Update%20Request


Appendices

Appendix A MicroDXP Specification

This section describes the first steps that should be taken to design hardware for a system incorporating the microDXP. XIA engineers will provide limited assistance with the actual design, depending on the support agreement.

A.1 Board Dimensions and Mounting The microDXP measures 3.375” x 2.125” (as shown in Figure. B.1),

with 0.120” non-plated mounting holes inset by 0.175” symmetrically with respect to each of the four corners. These mounting holes are intended for use with 4-40 or equivalent screws. An alternate board form factor includes 0.1875” blank PCB rails on the two long sides. The rails were included for systems where the microDXP board is to be mounted in a slot. The overall dimensions for the slot-mounted board are thus 3.375” x 2.500”.

Figure A.1: Dimensioned drawing with Preampflier Type Switch, Input Attenuation, and mounting hole locations.

A.2 Preamplifier Type Selector Switch The only hardware setting on the microDXP board is the preamplifier

type selector switch. The location of the miniature two-position slide switch S1 is displayed in Figure B.2. The two positions are silkscreen-labeled RAMP and OFFSET. Select RAMP for reset-type preamplifiers. Select OFFSET for RC-feedback preamplifiers.

3/18/2010 46


A.3 Input Signal Attenuation The voltage range of the preamplifier signal must not exceed the input

range of the microDXP, excluding reset transients that exceed the range for a few microseconds. The input range is specified below in Table B.0. To accommodate preamplifiers with an output range in excess of 6 Volts, an optional 6dB attenuation (divide by one-half) setting has been included in the Revision C microDXP input circuitry. 6dB attenuation, and the increased input range, are achieved by shorting with solder the two oval pads of R87 together. The microDXP Revision C is shipped by default with the solder short omitted.

MicroDXP Board Rev.

Input Range - 0dB Atten. (default - R87 clean)

Input Range - 6dB Atten. (R87 solder-short present)

B +/- 5.7 V N/A (R87 not included) C (C1) +/- 3.9 V +/- 7.8 V

Table A.1: The microDXP analog input range depends on the board revision and attenuation setting (Revision C only).

A.4 Connector Locations and Pinouts Two connectors carry all electronic signals to and from the microDXP

standard assembly, as depicted in Figure B.2. A 2-conductor, 1.25mm pitch connector carries the analog signal from the preamp. The mating connector is a crimp-type socket that accomodates 26-30AWG stranded wire. Table B.1 details the pin assignments of this connection. Note: The pinout is reversed relative to the microCOM board (see Error! Reference source not found.).

A single 30-conductor, 0.5mm pitch flat-flex interconnect carries all communications, power and auxiliary I/O to and from the microDXP. The flex cable provides for two dimensions of freedom, but does require alignment along the axis that bisects all of the contacts. The most likely error would be misalignmend of this interconnect, or a reversal of the pinout. Table B.2 details the pin assignments of the flex interconnect.

Figure A.2: MicroDXP connector locations and part numbers, TOP SIDE.

3/18/2010 47


Figure A.3: MicroDXP connector locations and part numbers, BOTTOM SIDE.

J1 - Analog Input: 2-pin compact right-angle header; or thru-hole LEMO. Hirose P/N: DF13-2P-1.25H (mating P/N: DF13-2S-1.25C; crimp contact P/N: DF13-2630SCFR) Pin #

Name Description

1 SIGNAL Preamplifier output signal 2 GND Internal ground connection

Table A.2: Pin assignments for the 2-conductor analog input connection.

3/18/2010 48


J12 – Flex Cable Port: 30-conductor, 0.5mm locking flex-cable connector; carries power, communications and auxiliary digital I/O Hirose P/N: FH12-30S-0.5SH (e.g. flat-flex cable, Parlex P/N: 0.5MM-30-x-B) Pin #

Name Description

1 +AVDD Positive DC supply voltage for analog signal conditioner: Regulated +5.0V; or unregulated +5.5V if on-board regulator present.

2 -AVSS Negative DC supply voltage for analog signal conditioner: Regulated -5.0V; or unregulated -5.5V if on-board regulator present.

3 GND Internal ground connection 4 +3.3VCC +3.3V DC supply for on-board digital components. 5 +3.3VCC +3.3V DC supply for on-board digital components. 6 GND Internal ground connection 7 SDA I2C data line 8 SCL I2C clock 9 ExtInt* External interrupt line, active low.

10 Gate* Inhibits data acquisition, active low. 11 GND Internal ground connection 12 RX RS-232 host receive (microDXP→host) 13 TX RS-232 host transmit (host→microDXP) 14 GND Internal ground connection 15 Vprog PIC programming voltage 16 ProgData PIC programming data line 17 ProgClk PIC programming clock 18 Aux0 Auxiliary configurable digital I/O line: connects to FiPPI 19 Aux1 Auxiliary configurable digital I/O line: connects to FiPPI 20 GND Internal ground connection 21 Aux2 Auxiliary configurable digital I/O line: connects to FiPPI 22 Aux3 Auxiliary configurable digital I/O line: connects to FiPPI 23 +3.3VCC +3.3V DC supply for on-board digital components. 24 SPORT_CLK DSP serial port clock line (ADSP218x SPORT) 25 GND Internal ground connection 26 SPORT_TDATA DSP serial port transmit data line (ADSP218x SPORT) 27 SPORT_TFS DSP serial port transmit frame sync line (ADSP218x SPORT) 28 GND Internal ground connection 29 SPORT_RDATA DSP serial port receive data line (ADSP218x SPORT) 30 SPORT_RFS DSP serial port receive frame sync line (ADSP218x SPORT)

Table A.3: Pin assignments for the 30-conductor flat-flex interconnect. The pinout is reversed relative to the microCOM board.

J11 – Board-to-Board Port: 50-conductor, 0.5mm mezzanine board-to-board receptacle; carries power, communications and auxiliary digital I/O Hirose P/N: DF12-50DS-0.5V (microCOM mating header P/N: DF12(5.0)-50DP-0.5V) Pin # Name Description Odd-numbered pins (top to bottom along the right-side of the connector as shown in Figure A.1)

1 +3.3VCC +3.3V DC supply for on-board digital components. 3 +3.3VCC +3.3V DC supply for on-board digital components. 5 +3.3VCC +3.3V DC supply for on-board digital components. 7 GND Internal ground connection 9 EAD15 IDMA data/address I/O line (MSB)

11 EAD14 IDMA data/address I/O line 13 EAD13 IDMA data/address I/O line

3/18/2010 49


15 EAD12 IDMA data/address I/O line 17 EAD11 IDMA data/address I/O line 19 EAD10 IDMA data/address I/O line 21 EAD9 IDMA data/address I/O line 23 EAD8 IDMA data/address I/O line 25 EAD7 IDMA data/address I/O line 27 EAD6 IDMA data/address I/O line 29 EAD5 IDMA data/address I/O line 31 EAD4 IDMA data/address I/O line 33 EAD3 IDMA data/address I/O line 35 EAD2 IDMA data/address I/O line 37 EAD1 IDMA data/address I/O line 39 EAD0 IDMA data/address I/O line (LSB) 41 GND Internal ground connection 43 EWR* IDMA write strobe (Active LO) 45 ESel* IDMA device select INPUT (must be asserted LO to communicate with the

microDXP) 47 ERdy* IDMA data ready (Active LO) OUTPUT 49 ERD* IDMA read strobe (Active LO)

Even-numbered pins (top to bottom along the left-side of the connector as shown in Figure A.1) 2 +AVDD Positive DC supply voltage for analog signal conditioner:

Regulated +5.0V; or unregulated +5.5V if on-board regulator present. 4 -AVSS Negative DC supply voltage for analog signal conditioner:

Regulated -5.0V; or unregulated -5.5V if on-board regulator present. 6 +3.3VCC +3.3V DC supply for on-board digital components. 8 GND Internal ground connection

10 SPORT_RFS DSP serial port receive frame sync line (ADSP218x SPORT) 12 SPORT_RDATA DSP serial port receive data line (ADSP218x SPORT) 14 GND Internal ground connection 16 SPORT_TFS DSP serial port transmit frame sync line (ADSP218x SPORT) 18 SPORT_TDATA DSP serial port transmit data line (ADSP218x SPORT) 20 GND Internal ground connection 22 SPORT_CLK DSP serial port clock line (ADSP218x SPORT) 24 GND Internal ground connection 26 Aux3 Auxiliary configurable digital I/O line: connects to FiPPI 28 Aux2 Auxiliary configurable digital I/O line: connects to FiPPI 30 Aux1 Auxiliary configurable digital I/O line: connects to FiPPI 32 Aux0 Auxiliary configurable digital I/O line: connects to FiPPI 34 Gate* Inhibits data acquisition, active low. 36 SCL I2C clock 38 SDA I2C data line 40 GND Internal ground connection 42 RX (B) RS-232 host receive (microDXP→host) via serial port B 44 TX (B) RS-232 host transmit (host→microDXP) via serial port B 46 GND Internal ground connection 48 EA/D* IDMA address (HI) / data (LO) selector INPUT 50 ExtInt* External interrupt line, active low.

Table A.4: Pin assignments for the 50-conductor board-to-board interconnect. The pinout is identical to the mating connector on the microDXP board.

3/18/2010 50


A.5 Power Supplies Note: Excessive ripple on the analog supplies (>20mVpp) can seriously degrade system performance. If +/-5.0V is supplied directly, either linear regulated or high-quality switching supplies should be used.

The microDXP requires three supply voltages to operate. A supply voltage of +3.3V is used to directly power most on-board digital circuitry, with minimal LC filtering at the board entry point. On-board voltage regulators also generate from this supply +3.0V for the ADC and +2.5V for the DSP. The total current requirement depends on the selected clock speed, ranging from 80mA to 130mA. The ripple requirements for this supply are not particularly stringent, though excessive radiated noise is to be avoided. If a switching supply is used, it should be well shielded from the microDXP.

Supply voltages of +/-5.5V are regulated on-board by default to generate +/-5.0V to power the analog components. The microDXP is thus intended to tolerate some conducted EMI (<100mV pk-pk) from switching supplies. The +/-5V analog regulators can be bypassed, and thus a slight reduction in power achieved, if low-noise (ie. linear or carefully designed switching) supplies are used. If the regulators are bypassed, only minimal LC filtering will be applied at the board entry point.

Current draw on the analog supplies is dominated by the optional variable-gain amplifier, which alone draws 12.5mA. The remaining analog circuitry draws roughly 10mA. The total required current is, conservatively, 15mA without variable-gain; 30mA with variable gain.

XIA plans to produce a more compact OEM power supply for the microDXP. We are considering a battery powered module with an I2C interface. Several designs are taking shape as we collect feedback from customers. XIA welcomes your advice and comments on this matter.

Regulated Supply Option: (<20mV pk-pk noise) Voltage Range Current (min) Current (max) Description +3.3V +/- 150mV 100mA 130mA Decent switching

supply +5.0V +/- 100mV 25mA 30mA Linear or high-

quality switching -5.0V +/- 100mV 25mA 30mA Linear or high-

quality switching Unregulated Supply Option (<100mV pk-pk noise) Voltage Range Current (min) Current (max) Description +3.3V +/- 150mV 100mA 130mA Decent switching

supply +5.5V to +6.0V 25mA 35mA Decent switching

supply -5.5V to –6.0V 25mA 35mA Decent switching

supply

Table A.5: Power supply specifications for the μDXP.

3/18/2010 51


Clock Speed

[MHz] Voltage Supply

Current [mA]

Power [mW]

Comment

8 VCC 89.7 296.0 +3.3V digital – includes ADC

8 V+ 20.3 101.5 +5V analog – includes VGA*

8 V- 23.3 116.5 -5V analog– includes VGA*

514 mW Total power consumption at 8MHz

16 VCC 103.0 339.9 +3.3V digital – includes

ADC 16 V+ 20.3 101.5 +5V analog – includes

VGA* 16 V- 23.3 116.5 -5V analog– includes

VGA* 557.9 mW Total power

consumption at 16MHz Table A.6: Power consumption by pipeline clock speed.

*The (optional) variable gain stage draws approximated 12.5mA.

3/18/2010 52


Appendix B System Development Outline

The microCOM board constitutes a simple routing adapter interface providing power and RS-232 communications access to the microDXP hardware as well as hardware access to some auxiliary I/O for the purposes of development, and serves test platform and design example for those users developing their own interface. This section describes the various options available and issues that must be considered if they are implemented.

The development process can be broken down as follows:

Figure B.1: Overview of development process for systems incorporating the μDXP.

1. Preliminary Specification: The detector and preamplifier are chosen. Basic performance goals are specified including energy resolution,

3/18/2010 53


throughput and nonlinearities. Power requirements are calculated. Host is specified and resources are calculated. Standard options such as clock speed(s) and variable gain are selected. Special functions, which may use the Auxiliary I/O, are defined. Preliminary consultation with an XIA engineer. Initial quotation is given based upon microDXP configuration, volume and required support level. One or more microDXP’s and USB Rapid Development Kits or RS232 Rapid Development Kits are purchased.

2. Preliminary Verification: Preliminary data acquisition using the microCOM hardware interface and microManager software. Energy resolution, throughput and linearity verified. Limited auxiliary functions explored.

3. Software Development: Implement low-level RS-232 commands for data acquisition. Decide whether to implement configuration command set. Choice is made based upon available host resources and time-to-market considerations. Code is implemented and tested with the microCOM hardware interface. Level of XIA software development support depends on the application.

4. Auxiliary I/O Development: Auxiliary circuitry such as I2C components are defined. PIC/DSP code is developed and tested using the microCOM, where possible—Note: some auxiliary functions cannot be exercised with the microCOM hardware interface. XIA extended support is required for systems that exercise auxiliary functions.

5. Revised Specification: Performance and functionality specifications are revised as necessary subsequent to preliminary development and testing. Follow-up consultation with an XIA engineer. Quotation updated to reflect any changes from preliminary specification.

6. Hardware Design, Manufacture and Test: Power supply for the microDXP, detector and preamplifier, a routing adapter or embedded host and optional auxiliary circuitry are designed, manufactured and individually tested.

7. Final Verification: Complete system test using the customer’s hardware and software. Design revisions made as necessary. Level of XIA hardware troubleshooting support depends on the application.

8. Production: microDXP hardware options and quality-control test procedures fixed, delivery schedule established. MicroDXP’s are shipped with precise firmware configuration (including all parameter settings) specified by customer.

3/18/2010 54


Appendix C Auxiliary I/O Functions

Note: This Appendix is only relevant to the RS232 Rapid Development Kit! Users of the USB Rapid Development Kit are encouraged to refer to the MicroComU Technical Reference Manual for the corresponding information for the MicroComU board. Most of these signals also exist and are accessible from the MicroComU board. However, they are on different connectors and pin numbers.

This Appendix briefly describes the auxiliary hardware functions that

can be exercised on the microCOM interface board. They are described in further detail in the MicroDXP Technical Reference Manual. The following auxiliaries are implemented in the delivered hardware, but not yet in the firmware and software. Please refer to the hardware drawing in Error! Reference source not found..

C.1 GATE* Input The GATE* signal, located at pin 10 of the flex interconnect, is a logic-

level input that disables data acquisition when asserted (LO). This function is the simplest implementation for real time external control of data acquisition. The GATE* signal is routed to a LEMO connector on the microCOM, as well as to a scope-probe test point.

C.2 Configurable I/O Lines Pins 18, 19, 21 and 22 are general-purpose digital I/O lines connected

to the FiPPI. These are not typically used, but may be dedicated in an embedded system as control outputs, e.g. used to switch pneumatic or electromechanical components in real-time based on acquired data, or as status lines driven by external circuitry, or both. Aux0 – Aux3 are routed to a SIP header on the microCOM for easy connection to external circuitry.

C.3 External Interrupt The external interrupt line, located at pin 9 of the flex interconnect,

provides a simple hook into the PIC-level control of the microDXP card. This could be used to signal a change in acquisition routine or perhaps to initiate or exit a sleep mode. The external interrupt can also be configured as general-purpose I/O, with direct access to the PIC.

C.4 I2C Bus The I2C bus provides for master/slave communications, where the PIC

is the master, via the industry-standard two-wire serial interface: SDA (data line) is located at pin 7, SCL (clock line) is located at pin 8 of the flex interconnect. I2C is a useful real-time control bus, allowing the PIC to monitor and/or control

3/18/2010 55


external circuitry. I2C components such as digital thermometers, DACs and memory, are inexpensive, readily available and easy to use. The microDXP reserves address 1001000 for an on-board temperature sensor and 1010010 for a serial EEPROM. Note: Currently only 7-bit I2C addresses are supported.

3/18/2010 56

Date post:	24-May-2020
Category:	Documents
Upload:	others
View:	5 times
Download:	0 times

microDXP - XIA...microDXP Rapid Development Kit User’s Manual Release 2.5.0 March 17, 2010...

Documents