7.3.4.3
Get Descriptor-String
Table 7-12. Get Descriptor-String
Value Meaning
Byte
Field
bmRequestType
bRequest
8051 Response
Set SUDPTR H-L to start of
Configuration Descriptor table in
RAM
0
1
2
3
0x80 IN, Device
0x06 “Get_Descriptor”
CFG String Number
wValueL
wValueH
0x02 Descriptor Type:
String
4
5
6
7
wIndexL
wIndexH
wLengthL
wLengthH
0x00 (Language ID L)
0x00 (Language ID H)
LenL
LenH
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
bmRequestType
bRequest
Value
Meaning
8051 Response
Read device descriptor data over
OUT0BUF
0
1
2
3
0x00 OUT, Device
0x07 “Set_Descriptor”
0x00
wValueL
wValueH
0x01 Descriptor Type:
Device
4
5
6
7
wIndexL
wIndexH
wLengthL
wLengthH
0x00
0x00
LenL
LenH
Page 7-16
Chapter 7. EZ-USB CPU
EZ-USB TRM v1.9
CYPRESS [ CYPRESS ]
