Soft USB Design Challenges

Lane Hauck

Systems EngineeringManager

Anchor Chips Inc.

laneh@ anchorchips.com

www.anchorchips.com

Soft USB Design Challenges

The Objective: SOFT

USBFunctionTraffic

Enhanced8051Core

3.3V, 24 MHz,4-clock cycle

ProgramandDataRAM

I/O

The Basic USB Interface

SerialInterfaceEngine(SIE)

D+

D-

Bytes

USBTranceiver

What the SIE Does

SerialInterfaceEngine(SIE)

D+

D-

USBTranceiver

SYNC

OUT

ADDR

ENDP

CRC5

Token Packet

SYNC

DATA1

PayloadData

CRC16

Data Packet

SYNC

ACK

SYNC

OUT

ADDR

ENDP

CRC5

Token Packet

SYNC

DATA0

PayloadData

CRC16

Data Packet

SYNC

ACK

H/S Pkt

PayloadData

PayloadData

ACK

A USB Control Transfer

SYNC

IN

ADDR

ENDP

CRC5

Token Packet

SYNC

DATA0

8bytesSetupData

CRC16

Data Packet

SYNC

H/S Pkt

SYNC

SETUP

ADDR

ENDP

CRC5

Token Packet

SYNC

DATA1

PayloadData

CRC16

Data Packet

SYNC

SYNC

IN

ADDR

ENDP

CRC5

Token Packet

SYNC

DATA0

PayloadData

CRC16

Data Packet

SYNC

H/S Pkt

SETUP Stage

DATA Stage

STATUS Stage

SYNC

DATA1

Data Packet

SYNC

H/S Pkt

SYNC

OUT

ADDR

ENDP

CRC5

Token Packet

CRC16

H/S Pkt

SerialInterfaceEngine(SIE)

8bytesSetupData

PayloadData

PayloadData

intelligence

ACK

ACK

ACK

ACK

ACK

EZ-USB Enhanced SIE

SerialInterfaceEngine(SIE)

intelligence

Anchor ChipsEnhanced SIE

FullDevice

Enumeration

Default Endpoints

Endpoint TypeAlternate Setting

0 1 2Max Packet Size (bytes)

0 CTL 64 64 641 IN INT 0 16 642 IN BULK 0 64 642 OUT BULK 0 64 644 IN BULK 0 64 644 OUT BULK 0 64 646 IN BULK 0 64 646 OUT BULK 0 64 648 IN ISO 0 16 2568 OUT ISO 0 16 2569 IN ISO 0 16 169 OUT ISO 0 16 1610 IN ISO 0 16 1610 OUT ISO 0 16 16

Advanced SIE Enumerates &Loads Code

SerialInterfaceEngine(SIE)

intelligence

Anchor Chips

Enhanced SIEFull

DeviceEnumeration

Enhanced8051Core

3.3V, 24 MHz,4-clock cycle

ProgramandDataRAM

Download & Upload

Code

The Download Request

Byte Field Value Meaning0 bmRequest 0x40 Vendor Request, OUT1 bRequest 0xA0 “Anchor Load”2 wValueL AddrL Starting address3 wValueH AddrH4 wIndexL 0x005 wIndexH 0x006 wLengthL LenL Number of Bytes7 wLengthH LenH

Final USB Device

intelligence

intelligence

Anchor ChipsEnhanced SIE

USBFunctionTraffic

Enhanced8051Core

3.3V, 24 MHz,4-clock cycle

ProgramandDataRAM

SerialInterfaceEngine(SIE)

intelligence

Anchor ChipsEnhanced SIE

I/O

AN2131Q Memory Map

Endpoint 0 IN

Endpoint 0 OUTEndpoint 1 IN

Endpoint 1 OUTEndpoint 2 IN

Endpoint 2 OUTEndpoint 3 IN

Endpoint 3 OUT

Endpoint 4 INEndpoint 4 OUT

Endpoint 5 INEndpoint 5 OUT

Endpoint 6 INEndpoint 6 OUTEndpoint 7 IN

Endpoint 7 OUT

EZ-USB regs

6.5K RAM

1024bytesBulk

EndpointBuffers

0000

1B40

1F3F

2000 1024 BytesIsochronous

FIFOS

1024 BytesIsochronous

FIFOS

SOF

USB

Endpoint 0 controlEndpoints 1-7 bulk/interruptEndpoints 8-15 isochronous

All 31 USB endpoints areavailable

USB

Enumeration

Host PCrecognizes deviceattachment, starts

Enumerationprocess

Host PC loadsloader driver,which loads

firmware anddescriptors intodevice from asoftware file

EZ-USB Coreprovides devicedescriptors to

identify the loaderdriver.

Host PC

Your Peripheral Device

The ReNumerationTM Process

The MagicHappens

Host PCrecognizes deviceattachment, starts

Enumerationprocess

Final USB device.EZ-USB CPU

services USB andprovides device

functionality

Host PC loadsloader driver,which loads

firmware anddescriptors intodevice from asoftware file

Host PCEnumeratesagain, loadsdevice driver

EZ-USB Coreprovides devicedescriptors to

identify the loaderdriver.

Host PC

Your Peripheral Device

Emulating a PhysicalDisconnect

DISCON#

EZ-USB

D-D+

5V

GND

To 3.3V Regulator

1234

1500

Using the Enhanced SIE

intelligence

intelligence

Anchor ChipsEnhanced SIE

USBFunctionTraffic

Enhanced8051Core

3.3V, 24 MHz,4-clock cycle

ProgramandDataRAM

SerialInterfaceEngine(SIE)

intelligence

Anchor ChipsEnhanced SIE

I/O

Get Descriptor--W ithout EnhancedSIE

CPU copies FIFO data to RAM, decodes"Get Descriptor" Request

USB Setup data copied to FIFO

SYNC

IN

ADDR

ENDP

CRC5

Token Packet

SYNC

DATA0

8 bytesSetupData

CRC16

Data Packet

SYNC

ACK

H/S Pkt

SYNC

SETUP

ADDR

ENDP

CRC5

Token Packet

SYNC

DATA1

PayloadData

CRC16

Data Packet

SYNC

DATA1

Data Packet

SYNC

ACK

SYNC

IN

ADDR

ENDP

CRC5

Token Packet

SYNC

DATA0

PayloadData

CRC16

Data Packet

SYNC

ACK

H/S Pkt

SYNC

ACK

H/S Pkt

SYNC

OUT

ADDR

ENDP

CRC5

Token Packet

CRC16

SETUP Stage

DATA Stage

STATUS Stage

EndpointFIFO

DescriptorData TableEndpoint

FIFO

1 2

4 53

6

1

2

3

4

5

6

CPU transfers first packet of data frommemory to endpoint FIFO.

FIFO Data sent in response to USB INtoken

CPU Transfers next packet of data frommemory to endpoint FIFO.

FIFO Data sent in response to USB INtoken

7 Repeat steps 5-6 as necessary.

8-byteSETUP data

buffer

H/S Pkt

Get Descriptor--W ith EnhancedSIE

SYNC

IN

ADDR

ENDP

CRC5

Token Packet

SYNC

DATA0

8 bytesSetupData

CRC16

Data Packet

SYNC

ACK

H/S Pkt

SYNC

SETUP

ADDR

ENDP

CRC5

Token Packet

SYNC

DATA1

PayloadData

CRC16

Data Packet

SYNC

DATA1

Data Packet

SYNC

ACK

SYNC

IN

ADDR

ENDP

CRC5

Token Packet

SYNC

DATA0

PayloadData

CRC16

Data Packet

SYNC

ACK

H/S Pkt

SYNC

ACK

H/S Pkt

SYNC

OUT

ADDR

ENDP

CRC5

Token Packet

CRC16

SETUP Stage

DATA Stage

STATUS Stage

8-byteSETUP data

buffer

1

8051 sets pointer to descriptor table in RAM,EZ-USB core does entire multi-packet transfer.

EZ-USB core copies Setup data directly to RAM,eliminating the FIFO-to-RAM copy step. 8051decodes the "Get Descriptor" request.

1

2

DescriptorData Table

2

H/S Pkt

Watch Those VID-PID-DIDs

EZ-USB

USBPC

Loads AnchorChips Driver

EZ-USB

Device ID (DID)

Product ID (PID)

Vendor ID (VID)

Serial EEPROM

USBPC

Loads Device-SpecificDriver

Device ID (DID)

Product ID (PID)

VID = 0547

(a) "Anchor Generic" Enumeration

(b) Custom Device Enumeration

IO Bandwidth Is Important

Accumulator

DPTR ISO OUT FIFO

FWR#

mo

vx a

,@d

ptr

D[7..0]

External FIFOor ASIC

Accumulator

DPTR ISO IN FIFO

D[7..0]

mo

vx @

dp

tr,a

FRD#External FIFO

or ASIC

AN2131 Transfers to ExternalFIFO

Expanding the AN2131Q

AN2131Q

PORTA (8)

PORTC (8)

PORTB (8)

Data (8)

RD#WR#

I2C

regOUT Pin

PIN

OE

Alternate Function

Address (16)

Lane Hauck

Systems EngineeringManager

Anchor Chips Inc.

laneh@ anchorchips.com

www.anchorchips.com