1

New method of video transfer and control functionsfor training in computer classroom and

for audiovisual applications

WP3: USB submodule

SCREENS – Tallin, 15 june 2006

EU CRAFT PROJECT 016357

2SCREENS – Tallin, 15 june 2006

USB module

CO

NN

EC

TO

RTo V

IDEO

BO

AR

D

HUB

ARM7

USB controller

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LPC221x

Internal FLASH

Debug UART

UART0

ISP1161A

USB HUB

UART1+ DIR

FLAGS

USB HOST PORT

USB DEVICE

PORT

CONNECTORTo VIDEO BOARDto/from

RS485to/from

AVRto

hostto

KBDto

MOUSE

USB module block diagram

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Software architecture

USB device service thread

USB device driver

USB host service thread

USB host driver

RS485protocolthread

Mode Supervisor & error management

AVR flags

USB hub

RS-485 network for USB data

AB

C

DPacket queue

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Operating modes

MODE AVRCODE A B C D

LOCKED1 - - - -

STANDALONE0 Y Y - -

REMOTE CONTROLLED2 Y - - Y

REMOTE CONTROLLER3 - Y Y -

USB device service thread

USB host service thread

RS485protocolthread

AB

C

DPacket queue

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USB stack selection, 1Commercial options:

• Express Logic

• Jungo

• RTCX

Traditional stacks on the market focus on mass storage (host and device) and HID class (device only); host and device stack are often sold separately.

Typical NRE fees range from 20k euros to 60k euros for the combined host & device stack; a minimum license quantity must be purchased in advance.

Homegrown minimal USB stack that matches requirements

starting from Philips libraries

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USB stack selection, 2Philips semiconductors offers unsupported libraries dedicated to the ISP1161A for host and device control.

• Available under NDA only, no fees associated• three sw models: host only, device only, simultaneous host and device• DOS version: does not assume presence of an underlying OS with USB libraries• bugs are present

ISP1161x Simultaneous Host-and-Device Mode Software Model

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Development tools selection, 1Several alternatives available:

• Keil MDK-ARM: RealView Microcontroller Development Kit for the ARM • IAR Embedded Workbench• Rowley Associates Crossworks for ARM• Green Hills (too expensive)

And the winner was………

Reasons:• Lowest cost• supports inexpensive JTAG probes• based on GNU tools• dedicated to ARM7 devices • good feeling during the 30-day evaluation period

Highlights:• CrossStudio Integrated IDE• integrated programming of internal FLASH (not available on all competitors)

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Development tools selection, 2

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Development tools selection, 3

Crossworks

Support packages for the following processors:

• Atmel AT91SAM7 (ARM7 core)• Luminary Micro LM3Sxxx (ARM Cortex M3 core)• Philips LPC2xxx (ARM7 core)• ST Microelectronics STA2051, STR71x, STR31x (ARM7)• SHARP LH75401, LH79520, LH79524

Several development boards are supported with specific code; among them:

• Olimex LPC-E2214 (a superset of the LPC-H2214 we have been using)

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Development tools selection, 4Board used for getting more familiar with the microcontroller

OLIMEX LPC-H2214

• Inexpensive• micro + SRAM + FLASH + serial ports (one of them via USB2serial converter)

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Test environment, 1

PHASE A: analysis on host of USB transactions

Using an open-source application for Windows, we have analyzed USB Messages between host controller and USB peripheral

USB Snoopy: USB traffic viewer

• Works on a Windows machine • it translates all data sent and received by the original windows driver in a more human readable form and writes this result in a big ascii file

Alternative: Bus Hound, commercial product from Perisoft: www.perisoft.com

http://sourceforge.net/projects/usbsnoop/

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Test environment, 2PHASE A: analysis on host of USB transactions

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Test environment, 3______________________________________________________________________________1 in down n/a 0.219 GET_DESCRIPTOR_FROM_DEVICEURB Header (length: 80)SequenceNumber: 1Function: 000b (GET_DESCRIPTOR_FROM_DEVICE)

________________________________________________________________________________1 in up n/a 0.235 CONTROL_TRANSFER 12 01 10 01 00 00 00 08 0x00000000URB Header (length: 80)SequenceNumber: 1Function: 0008 (CONTROL_TRANSFER)PipeHandle: 82ff64a8

SetupPacket:0000: 80 06 00 01 00 00 12 00 bmRequestType: 80 DIR: Device-To-Host TYPE: Standard RECIPIENT: DevicebRequest: 06 GET_DESCRIPTORDescriptor Type: 0x0001 DEVICE

TransferBuffer: 0x00000012 (18) length0000: 12 01 10 01 00 00 00 08 6d 04 0c c0 10 21 01 02 0010: 00 01 bLength : 0x12 (18) bDescriptorType : 0x01 (1) bcdUSB : 0x0110 (272) bDeviceClass : 0x00 (0) bDeviceSubClass : 0x00 (0) bDeviceProtocol : 0x00 (0) bMaxPacketSize0 : 0x08 (8) idVendor : 0x046d (1133) idProduct : 0xc00c (49164) bcdDevice : 0x2110 (8464) iManufacturer : 0x01 (1) iProduct : 0x02 (2) iSerialNumber : 0x00 (0) bNumConfigurations : 0x01 (1)

connecting a USB mouse

Retrieval of device descriptor

Downstream (from host to device)

Upstream (device reply)

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Test environment, 4________________________________________________________________________________2 in down n/a 0.235 GET_DESCRIPTOR_FROM_DEVICEURB Header (length: 80)SequenceNumber: 2Function: 000b (GET_DESCRIPTOR_FROM_DEVICE)

________________________________________________________________________________2 in up n/a 0.235 CONTROL_TRANSFER 09 02 22 00 01 01 00 a0 0x00000000URB Header (length: 80)SequenceNumber: 2Function: 0008 (CONTROL_TRANSFER)PipeHandle: 82ff64a8

SetupPacket:0000: 80 06 00 02 00 00 09 00 bmRequestType: 80 DIR: Device-To-Host TYPE: Standard RECIPIENT: DevicebRequest: 06 GET_DESCRIPTORDescriptor Type: 0x0002 CONFIGURATION

TransferBuffer: 0x00000009 (9) length0000: 09 02 22 00 01 01 00 a0 32 bLength : 0x09 (9) bDescriptorType : 0x02 (2) wTotalLength : 0x0022 (34) bNumInterfaces : 0x01 (1) bConfigurationValue: 0x01 (1) iConfiguration : 0x00 (0) bmAttributes : 0xa0 (160) MaxPower : 0x32 (50)

connecting a USB mouse

Retrieval of configuration descriptor

Downstream (from host to device)

Upstream (device reply)

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Test environment, 5________________________________________________________________________________5 out down n/a 0.281 CLASS_INTERFACE -URB Header (length: 80)SequenceNumber: 5Function: 001b (CLASS_INTERFACE)PipeHandle: 00000000

SetupPacket:0000: 22 0a 00 00 00 00 00 00 bmRequestType: 22 DIR: Host-To-Device TYPE: Class RECIPIENT: EndpointbRequest: 0a

No TransferBuffer

________________________________________________________________________________5 out up n/a 0.281 CONTROL_TRANSFER - 0x00000000URB Header (length: 80)SequenceNumber: 5Function: 0008 (CONTROL_TRANSFER)PipeHandle: 82ff64a8

SetupPacket:0000: 21 0a 00 00 00 00 00 00 bmRequestType: 21 DIR: Host-To-Device TYPE: Class RECIPIENT: InterfacebRequest: 0a

No TransferBuffer

connecting a USB mouse

Retrieval of class type

17

Board under test, 1

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18

Board under test, 2

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Serial-to-USB

converter

ARM7JTAG

emulator

debugserial port

USB connector adapter(replicating USB

connectors on Video Board)

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RS-485 protocol, 1

Low-level protocol: binary, with 8-bit CRC and escape sequences (to avoid persistent out-of-sync situations)

General data packet:<STX> <CMD> <LEN> <data>…<data> <CRC> <EOX>

where:STX = Start of PacketCMD = command (write, read)LEN = number of data bytes, excluding CRC; it may be zero CRC = CRC of all bytes from CMD to last dataEOX = End of Packet

STX, EOX: unique byte valuesIf the same must transmitted, it is substituted with a 2-byte sequence, as follows:STX = 0x02, EOX = 0x04, ESC = 0x10Inserted data byte = value OR 0x80 (modified since last meeting)

Then:0x10 0x82 means a value of 0x020x10 0x84 means a value of 0x040x10 0x90 means a value of 0x10

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RS-485 protocol, 2

Internal debug tool for exercising the RS-485 protocol on standard RS-232 connection; protocol is decoded on-the-fly

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RS-485 protocol, 3

STXCMD LEN EOX

CRCdata[0]

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Current status

Hardware realization

• PCB layout completed, prototype fabrication completed• fully RoHS compliant• power control of USB ports included• prototypes debugged and in use

Software development

• RS-485 protocol completed• low-level driver for ISP1161A completed• minimal USB host stack completed• minimal USB device stack completed• debug, integration and fine tuning: in progress

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THANK YOU