Table 7-2. How the 8051 Handles USB Device Requests (ReNum=1)
bRequest
0x00
0x01
0x02
0x03
0x04
0x05
0x06
0x07
0x08
0x09
0x0A
0x0B
0x0C
Name
Get Status
Action
SUDAV Interrupt
SUDAV Interrupt
none
8051 Response
Supply RemWU, SelfPwr or Stall bits
Clear RemWU, SelfPwr or Stall bits
Stall EP0
Clear Feature
(reserved)
Set Feature
(reserved)
SUDAV Interrupt
none
Set RemWU, SelfPwr or Stall bits
Stall EP0
Set Address
Get Descriptor
Set Descriptor
Update FNADDR register none
SUDAV Interrupt
SUDAV Interrupt
Supply table data over EP0-IN
Application dependent
Get Configuration SUDAV Interrupt
Set Configuration SUDAV Interrupt
Send current configuration number
Change current configuration
Supply alternate setting No. from RAM
Change alternate setting No.
Get Interface
Set Interface
Sync Frame
SUDAV Interrupt
SUDAV Interrupt
SUDAV Interrupt
Supply a frame number over EP0-IN
Vendor Requests
0xA0 (Firmware Load)
0xA1 - 0xAF
Up/Download RAM
SUDAV Interrupt
SUDAV Interrupt
---
Reserved by Cypress Semiconductor
Depends on application
All except 0xA0
In the ReNumerated condition (ReNum=1), the EZ-USB core passes all USB requests
except Set Address onto the 8051 via the SUDAV interrupt. This, in conjunction with the
USB disconnect/connect feature, allows a completely new and different USB device
(yours) to be characterized by the downloaded firmware.
The EZ-USB core implements one vendor-specific request, namely “Firmware Load,”
0xA0. (The bRequest value of 0xA0 is valid only if byte 0 of the request, bmRequest-
Type, is also “x10xxxxx,” indicating a vendor-specific request.) The load request is valid
at all times, so even after ReNumeration the load feature maybe used. If your application
implements vendor-specific USB requests, and you do not wish to use the Firmware Load
feature, be sure to refrain from using the bRequest value 0xA0 for your custom requests.
The Firmware Load feature is fully described in Chapter 5, "EZ-USB Enumeration and
ReNumeration ."
Note
To avoid future incompatibilities, vendor requests A0-AF (hex) are reserved by Cypress
Semiconductor.
Page 7-6
Chapter 7. EZ-USB CPU
EZ-USB TRM v1.9
CYPRESS [ CYPRESS ]
