Post on 14-Apr-2018
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USB Device Controller(on LPC2148)
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INDEX
1. INTRODUCTION
2. USB CONTROLLER
3. ARCHITECTURE OF LPC2148
4. USB DEVICE CONTROLLER ON LPC2148
5. SPECIAL FEATURES
6. ADVANTAGES
7. APPLICATIONS
8. REFERENCES
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Introduction
Since USB is a standard doesnt that make all
microcontrollers with USB the same?
NO!!
Architectural choices and implementation detailsmake a big difference in performance and ease ofuse.
LPC2148 is a microcontroller which gives bestperformance as a USB device.
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Universal Serial Bus
4-wire protocol for serial communication.
Host controlled protocol.
Flexibility 3 data transfer rates
4 transfer types
Has replaced all serial and parallel interfaces with itsoutstanding features
Layered protocol.
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USB Controller
USB is layered protocol. Has defined format for data transfer. Each USB peripheral must have USB controller. Functions of USB controllers
To implement USB protocol. To handle details of formatting data
To add bits for error checking. To check received data for errors. To send and receive individual bits on the bus.
To simplify design process by taking care of lower layers ofprotocol. Types
Host controller Gives functionality of host to peripheral. Device controller Gives functionality of device to peripheral.
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On-chip
USB Device ControllerOf
LPC2148.
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LPC2148
Features -
32 - bit microcontroller based on ARM7TDMI-S CPU.
512kB of on chip FLASH memory.
40kB of on-chip SRAM memory. ISP/IAP allows fast FLASH programming.
On chip peripherals
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LPC2148 Architecture
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Features
Allows LPC2148 to be configured as USB device only.
Fully compliant with USB2.0 full speed specification.
Supports 32 physical endpoints.
Scalable realization of endpoints.
Double buffering supported.
Supports DMA transfer on all non-control endpoints .
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Features (Continued)
Supports all four types of data transfer.
Supports SoftConnect feature.
Supports Good link LED indicator.
Flexible clock architecture.
Remote wakeup.
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Architecture of USB Device Controller
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USB Registers
Device Registers
Endpoint Registers
DMA Registers
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Transfer Modes
USB Device Controller supports two modes of transfer
Slave mode transfer
DMA mode transfer
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Slave mode transfer
USB Block acts like a slave
It can only issue interrupts to the CPU
Control EP uses this mode of transfer exclusively
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DMA mode transfer
USB Block acts like a Master
Will transfer data directly from the 8K SRAM to the EP_RAM and
vice-versa.
For Isochronous transfers, the DMA transfer is synchronized to the
frame interrupt
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LPC2148 USB Connections
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Special Features ( by NXP)
Soft connect
Can connect/re-connect to the host through software
No need to unplug and plug the cable back again
Remote wakeup Good-link LED
Needs a shared GPIO pin
Shows indication on a LED if connection is established
Double buffer
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ARM & USB Advantages
ARM Low power consumption.
Low cost.
High data processing
capacity.
Licensable.
USB Hot pluggable.
Automatic configuration.
Flexibility.
One interface for many
devices.
Self powered.
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APPLICATIONS
Industrial control
Consumer electronics
-Mobile phone
-DVD-Gaming
-Set top box
-Audio Video
Networking
-Modems
-Gateways
Data storage
-hard disk drives-flash
Imaging
-Digital camera
-Printer
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Books1.UM10139 User manual of LPC2148.
2. USB Complete by Jan Axelson.
3. USB in a Nutshell.
Websites1. www.keil.com
2. www.nxp.com
THANK YOU!!!