SD Card Data Logger

Senior Design I

Mid-Semester Presentation

Sep 30, 2010

TEAM

Team Advisor:

Dr. Patrick Donohoe

James Felkins (EE)

Team Leader,

Testing, Web Design

Harry Corey (EE)

Testing, Hardware Design, Software Design

Brendan Babiak (EE)

Software & Hardware Design, Prototype Construction

Jaron Martin (CPE)

Lead Software Design, Prototype Construction

OUTLINE

-Description of S-Drive

-The Problem

-The Solution

-Design constraints

-System overview

-Tradeoffs

-Timeline

-Progress

WHAT IS THE S-DRIVE?

The S-Drive is an OEM module that accepts data through a serial connection and saves it to an SD card.

THE PROBLEM

SD cards are a viable storage medium with unique advantages but involve complex overhead.

SOLUTION

The S-Drive will handle the unwanted overhead and make SD cards a more desirable solution.

TECHNICAL CONSTRAINTS

Name Description

Communication The device must have UART and SPI data connections.

VoltageThe device must support an input voltage between 3.3 and 5 V.

Current DrawThe device must draw a maximum current of 250 mA in active mode, 200 uA in sleep mode, and 10 uA in deep-sleep mode.

Storage MediumThe device must interface with a standard size, 32 x 24 x 2.1 mm SD card.

Memory The device must support all SD cards up to 32 GB.

TECH CONSTRAINTS, CON’T

[1]

SD Version

Name Maximum Capacity

SD 1.x SD 1 GB (revised to support 4 GB)

SD 2.0 SDHC 32 GB

SD 3.0 SDXC 2 TB

A standard-sized SD socket allows for increase compatibility across different sizes of SD cards.

32GB was chosen to support all SD cards through the SD 2.0 specification.

PRACTICAL CONSTRAINTS -

ECONOMICThe device must cost less than $60.

Competitor Price

VDRIVE2 $24.50 [4]

Logomatic v2 $59.95 [3]

Avisaro M20511 99.00 € (~$133) [2]

[2]

[4][3]

PRACTICAL CONSTRAINTS - MANUFACTURABILITYThe device must easily fit and integrate into other systems.

•Provided on a PCB

•No larger than 5 in2

•Easily mountable

SYSTEM OVERVIEW

SYSTEM OVERVIEW

SYSTEM OVERVIEW

SYSTEM OVERVIEW

SYSTEM OVERVIEW

SYSTEM OVERVIEW

SYSTEM OVERVIEW

TRADEOFFS – FILE ALLOWANCENumber of Simultaneous Open Files Allowed

Convenience to the User

Percent of remaining RAM available for buffer (%)

How often SD card must be powered on

1 Least convenient 100 Least often

2 More convenient 50 More often

More than 2 Most convenient < 33.3 Most often

TRADEOFFS - MICROS

PIC Available FAT libraries?

Available from Manufacturer?

Available Program Memory (kB)

RAM(KiB) Estimated Sleep Current Draw

PIC24FJ64GA102

Yes Yes 64 8 ~10 uA

PIC24HJ32GP202

Yes Yes 32 2 ~100 uA

TIMELINE

Month August September October November

Research

Hardware design

Programming

Prototyping

Testing

Final Prototype

TASKS ACCOMPLISHED

Hardware Design

Ordered Parts

-Microcontroller

-SD card socket

Prototype construction

-SD card socket installed

-Power supply

Began software development

-Successfully written data to an SD card

PROTOTYPING

PROTOTYPING

FUTURE TASKS

Finish software development

-SD card initialization routines

-FAT16, FAT32 file system management

-input configuration

-buffering scheme

SUMMARY

Problem• SD card overhead is burdensome

Solution• S-Drive will handle overhead

Design Constraints• packaging, current draw, etc.

Technical Tradeoffs• File Allowance (1, 2, or more)• Microcontrollers (PIC24H vs. PIC24F)

REFERENCES[7] Microchip, “PIC24F Family Reference Manual, Sect. 21 UART,” Microchip Technology Inc., January 26, 2010. [Online] . Available: http://ww1.microchip.com/downloads/en/DeviceDoc/en026583.pdf. [Accessed September 14, 2010].

[8] Microchip, “PIC24F Family Reference Manual, Sect. 23 Serial Peripheral Interface (SPI),” Microchip Technology Inc., March 22, 2007. [Online] . Available:http://ww1.microchip.com/downloads/en/DeviceDoc/39699b.pdf. [Accessed September 14, 2010].

[9] STEC, “SLDSxxxBS(I)U Data Sheet,” STEC Inc., March 2008. [Online] . Available: http://www.stec-inc.com/downloads/flash_datasheets/SLSDxxxB_I_U61000-05203.pdf. [Accessed September 14, 2010].

[10] Sparkfun Electronics, “Logomatic v2 Serial SD Datalogger,” On-Line Store,2010.[Online].Available:http://www.sparkfun.com/commerce/product_info.php?products_id=8627. [Accessed:September 14, 2010].

[11] C-ONE Technology Corp., “Wide Temperature Industrial SD Card Product Specification,” May 2010. [Online]. Available: http://www.psism.com/c-1sd.pdf. [Accessed: September 14, 2010].

 

QUESTIONS?