Table 7-5. Get Status-Interface
Value Meaning
Byte
0
Field
bmRequestType
bRequest
wValueL
8051 Response
Load two bytes into IN0BUF
Byte 0 : zero
0x81 IN, Endpoint
1
0x00 “Get Status”
2
0x00
Byte 1 : zero
3
wValueH
0x00
4
wIndexL
0x00
5
wIndexH
0x00
6
wLengthL
wLengthH
0x02 Two bytes requested
7
0x00
Get_Status/Interface is easy: the 8051 returns two zero bytes through IN0BUF and clears
the HSNAK bit. The requested bytes are shown as “Reserved (Reset to zero)” in the USB
Specification
7.3.2 Set Feature
Set Feature is used to enable remote wakeup or stall an endpoint. No data stage is
required.
Table 7-6. Set Feature-Device (Set Remote Wakeup Bit)
Byte
Field
bmRequestType
bRequest
Value
Meaning
8051 Response
0
1
2
0x00 OUT, Device
0x03 “Set Feature”
Set the Remote Wakeup bit
wValueL
0x01 Feature Selector:
Remote Wakeup
3
4
5
6
7
wValueH
wIndexL
wIndexH
wLengthL
wLengthH
0x00
0x00
0x00
0x00
0x00
The only Set_Feature/Device request presently defined in the USB specification is to set
the remote wakeup bit. This is the same bit reported back to the host as a result of a Get
Status-Device request (Table 7-3). The host uses this bit to enable or disable remote
wakeup by the device.
Page 7-10
Chapter 7. EZ-USB CPU
EZ-USB TRM v1.9
CYPRESS [ CYPRESS ]
