RM0090: Reference manual - STMicroelectronics

USB on-the-go full-speed (OTG_FS) RM0090
OTG_FS reset register (OTG_FS_GRSTCTL)
Address offset: 0x10
Reset value: 0x2000 0000
The application uses this register to reset various hardware features inside the core.
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
AHBIDL
Reserved
1053/1416 Doc ID 018909 Rev 3
TXFNUM
r rw rs rs rs rs rs
Bit 31 AHBIDL: AHB master idle
Indicates that the AHB master state machine is in the Idle condition.
Note: Accessible in both device and host modes.
Bits 30:11 Reserved, must be kept at reset value.
Bits 10:6 TXFNUM: TxFIFO number
This is the FIFO number that must be flushed using the TxFIFO Flush bit. This field must not
be changed until the core clears the TxFIFO Flush bit.
00000:
– Non-periodic TxFIFO flush in host mode
– Tx FIFO 0 flush in device mode
00001:
– Periodic TxFIFO flush in host mode
– TXFIFO 1 flush in device mode
00010: TXFIFO 2 flush in device mode
...
00101: TXFIFO 15 flush in device mode
10000: Flush all the transmit FIFOs in device or host mode.
Note: Accessible in both device and host modes.
Bit 5 TXFFLSH: TxFIFO flush
This bit selectively flushes a single or all transmit FIFOs, but cannot do so if the core is in the
midst of a transaction.
The application must write this bit only after checking that the core is neither writing to the
TxFIFO nor reading from the TxFIFO. Verify using these registers:
Read—NAK Effective Interrupt ensures the core is not reading from the FIFO
Write—AHBIDL bit in OTG_FS_GRSTCTL ensures the core is not writing anything to the
FIFO.
Note: Accessible in both device and host modes.
Bit 4 RXFFLSH: RxFIFO flush
The application can flush the entire RxFIFO using this bit, but must first ensure that the core
is not in the middle of a transaction.
The application must only write to this bit after checking that the core is neither reading from
the RxFIFO nor writing to the RxFIFO.
The application must wait until the bit is cleared before performing any other operations. This
bit requires 8 clocks (slowest of PHY or AHB clock) to clear.
Note: Accessible in both device and host modes.
Bit 3 Reserved, must be kept at reset value.
TXFFLSH
RXFFLSH
Reserved
FCRST
HSRST
CSRST