RM0090: Reference manual - STMicroelectronics

RM0090 USB on-the-go full-speed (OTG_FS)
Host mode:
OTG_FS Receive status debug read/OTG status read and pop registers
(OTG_FS_GRXSTSR/OTG_FS_GRXSTSP)
Address offset for Read: 0x01C
Address offset for Pop: 0x020
Reset value: 0x0000 0000
A read to the Receive status debug read register returns the contents of the top of the
Receive FIFO. A read to the Receive status read and pop register additionally pops the top
data entry out of the RxFIFO.
The receive status contents must be interpreted differently in host and device modes. The
core ignores the receive status pop/read when the receive FIFO is empty and returns a
value of 0x0000 0000. The application must only pop the Receive Status FIFO when the
Receive FIFO non-empty bit of the Core interrupt register (RXFLVL bit in
OTG_FS_GINTSTS) is asserted.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Reserved
Bits 31:21 Reserved, must be kept at reset value.
Bits 20:17 PKTSTS: Packet status
Indicates the status of the received packet
0010: IN data packet received
0011: IN transfer completed (triggers an interrupt)
0101: Data toggle error (triggers an interrupt)
0111: Channel halted (triggers an interrupt)
Others: Reserved
Bits 16:15 DPID: Data PID
Indicates the Data PID of the received packet
00: DATA0
10: DATA1
01: DATA2
11: MDATA
PKTSTS DPID BCNT CHNUM
Bits 14:4 BCNT: Byte count
Indicates the byte count of the received IN data packet.
r r r r
Bits 3:0 CHNUM: Channel number
Indicates the channel number to which the current received packet belongs.
Doc ID 018909 Rev 3 1062/1416