CHAPTER 12 USB FUNCTION CONTROLLER (USBF)
Preliminary User’s Manual U19014EJ1V0UD
297
(2/2)
Bit position
Bit name
Function
2
STG
This bit is set to 1 when the stage of control transfer has changed to the status stage. It
is valid for both FW-processed and hardware-processed requests. This bit is also set to
1 when the stage of control transfer (without data) has changed to the status stage.
1: Status stage (interrupt request is generated)
0: Not status stage (default value)
This bit is automatically cleared to 0 by hardware when the next SETUP token is
received.
It is also set to 1 when the stage of control transfer has changed to the status stage
while ACK cannot be correctly received in the data stage. In this case, the EP0NKW bit
of the UF0E0N register is also cleared to 0 as soon as the UF0E0W register has been
cleared, if the FW is processing control transfer (read).
1
PROT
This bit indicates that a SETUP token has been received. It is valid for both FW-
processed and hardware-processed requests.
1: SETUP token is correctly received (interrupt request is generated).
0: SETUP token is not received (default value).
This bit is set to 1 when data has been correctly received in the UF0E0ST register.
Clear this bit to 0 by FW when the first read access is made to the UF0E0ST register. If
it is not cleared to 0 by FW, reception of the next SETUP token cannot be correctly
recognized.
This bit is used to accurately recognize that a SETUP transaction has been executed
again during control transfer. If the SETUP transaction is re-executed during control
transfer and if a second request is executed by hardware, the CPUDEC bit is not set to
1, but the PROT bit can be used for recognition of the re-execution.
0
CPUDEC
This bit indicates that the UF0E0ST register has a request that is to be decoded by FW.
1: Data is in UF0E0ST register (interrupt request is generated).
0: Data is not in UF0E0ST register (default value).
This bit is automatically cleared to 0 by hardware when all the data of the UF0E0ST
register is read.
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