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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!!!