EZ-USB Datasheet, PDF (137/334 Pages) Cypress Semiconductor – The EZ-USB USB Integrated Circuit

7.3.4.3 Get Descriptor-String
Table 7-12. Get Descriptor-String
Byte
Field
0 bmRequestType
1 bRequest
2 wValueL
3 wValueH
4 wIndexL
5 wIndexH
6 wLengthL
7 wLengthH
Value
Meaning
0x80 IN, Device
0x06 “Get_Descriptor”
CFG String Number
0x02 Descriptor Type:
String
0x00 (Language ID L)
0x00 (Language ID H)
LenL
LenH
8051 Response
Set SUDPTR H-L to start of
Configuration Descriptor table in
RAM
Configuration and string descriptors are handled similarly to device descriptors. The 8051
firmware reads byte 2 of the SETUP data to determine which configuration or string is
being requested, loads the corresponding table pointer into SUDPTRH-L, and the EZ-
USB core does the rest.
7.3.5 Set Descriptor
Table 7-13. Set Descriptor-Device
Byte
Field
0 bmRequestType
1 bRequest
2 wValueL
3 wValueH
4 wIndexL
5 wIndexH
6 wLengthL
7 wLengthH
Value
Meaning
0x00 OUT, Device
0x07 “Set_Descriptor”
0x00
0x01 Descriptor Type:
Device
0x00
0x00
LenL
LenH
8051 Response
Read device descriptor data over
OUT0BUF
Page 7-16
Chapter 7. EZ-USB CPU
EZ-USB TRM v1.9