CY7C656xx

Document Number: 38-08037 Rev. *S

Page 10 of 28

Default Descriptors

This section presents the different descriptors that are available. The following tables list the functionality of each descriptor.

Device Descriptor

The standard device descriptor for CY7C656xx is based on the information found in the SPI EEPROM. The information in the

EEPROM overrides the default descriptor values. If no EEPROM is used, the CY7C656xx enumerates with the default descriptor

values as shown in the following table. If a blank EEPROM is connected, the hub enumerates as vendor defined class instead of a

hub class. This is for the purpose of programming the EEPROM with the Cypress driver.

Configuration Descriptor

Byte

Full Speed

High Speed

Field Name

Description

0

0x12

0x12

bLength

18 bytes

1

0x01

0x01

bDescriptorType

DEVICE_DESCRIPTOR

2,3

0x0110

0x0200

bcdUSB

USB specification 2.0 (1.1 if forced FS)

4

0x09

0x09

bDeviceClass

HUB

5

0x00

0x00

bDeviceSubClass

None

6

0x00

0x01

bDeviceProtocol

None

7

0x40

0x40

bMaxPacketSize0

64 bytes

8,9

0x04B4

0x04B4

wIdVendor

VID (overridden by what is defined in EEPROM)

10,11

0x6560

0x6560

wIdProduct

PID (overridden by what is defined in EEPROM)

12, 13

0x0915

0x0915

wbcdDevice

DID (overridden by what is defined in EEPROM)

14

0x00

0x00

iManufacturer

Overridden by EEPROM

15

0x00

0x00

iProduct

Overridden by EEPROM

16

0x00

0x00

iSerialNumber

Overridden by EEPROM

17

0x01

0x01

bNumConfigurations

One configuration supported

Byte

Full Speed

High Speed

Field Name

Description

0

0x09

0x09

bLength

9 bytes

1

0x02[4]/0x07[5]

0x02[4]/0x07[5] bDescriptorType

CONFIG_DESCRIPTOR

2

0x0019

0x0019

wTotalLength

Length of all other descriptors

4

0x01

0x01

bNumInterfaces

1

5

0x01

0x01

bConfigurationValue

The configuration to use

6

0x00

0x00

iConfiguration

7

0xA0

0xE0

0xA0

0xE0

bmAttributes

Value depends on pin 45 - SELFPWR signal

SELFPWR = 0 yields 0xA0 and =1 yields 0xE0

8

0x28

0x57[4]

bMaxPower

Notes

4. Configured speed descriptor.

5. Other speed descriptor.

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