STMicroelectronics STM32F405 Reference Manual page 1448

USB on-the-go high-speed (OTG_HS)
Bit 31 EPENA: Endpoint enable
– SETUP phase done
– Endpoint disabled
– Transfer completed
Bit 30 EPDIS: Endpoint disable
Bit 29 SODDFRM: Set odd frame
Bit 28 SD0PID: Set DATA0 PID
SEVNFRM: Set even frame
Bit 27 SNAK: Set NAK
Bit 26 CNAK: Clear NAK
Bits 25:22 Reserved, must be kept at reset value.
Bit 21 STALL: STALL handshake
Applies to noncontrol, nonisochronous OUT endpoints only (access type is rw).
Applies to control endpoints only (access type is rs).
Bit 20 SNPM: Snoop mode
1448/1731
Applies to IN and OUT endpoints.
The application sets this bit to start transmitting data on an endpoint.
The core clears this bit before setting any of the following interrupts on this endpoint:
The application sets this bit to stop transmitting/receiving data on an endpoint, even before
the transfer for that endpoint is complete. The application must wait for the Endpoint
disabled interrupt before treating the endpoint as disabled. The core clears this bit before
setting the Endpoint disabled interrupt. The application must set this bit only if Endpoint
enable is already set for this endpoint.
Applies to isochronous OUT endpoints only.
Writing to this field sets the Even/Odd frame (EONUM) field to odd frame.
Applies to interrupt/bulk OUT endpoints only.
Writing to this field sets the endpoint data PID (DPID) field in this register to DATA0.
Applies to isochronous OUT endpoints only.
Writing to this field sets the Even/Odd frame (EONUM) field to even frame.
A write to this bit sets the NAK bit for the endpoint.
Using this bit, the application can control the transmission of NAK handshakes on an
endpoint. The core can also set this bit for OUT endpoints on a Transfer Completed
interrupt, or after a SETUP is received on the endpoint.
A write to this bit clears the NAK bit for the endpoint.
The application sets this bit to stall all tokens from the USB host to this endpoint. If a NAK
bit, Global IN NAK, or Global OUT NAK is set along with this bit, the STALL bit takes
priority. Only the application can clear this bit, never the core.
The application can only set this bit, and the core clears it, when a SETUP token is received
for this endpoint. If a NAK bit, Global IN NAK, or Global OUT NAK is set along with this bit,
the STALL bit takes priority. Irrespective of this bit's setting, the core always responds to
SETUP data packets with an ACK handshake.
This bit configures the endpoint to Snoop mode. In Snoop mode, the core does not check
the correctness of OUT packets before transferring them to application memory.
DocID018909 Rev 11
RM0090