Pipe Reset

A pipe can be reset at any time by writing a one to the Pipe x Reset (USBHS_HSTPIP.PRSTx) bit. This is recommended before using a pipe upon hardware reset or when a USB bus reset has been sent. This resets:

• the internal state machine of the pipe,
• the receive and transmit bank FIFO counters,
• all the registers of the pipe (USBHS_HSTPIPCFGx, USBHS_HSTPIPISRx, USBHS_HSTPIPIMRx), except its configuration (USBHS_HSTPIPCFGx.ALLOC, USBHS_HSTPIPCFGx.PBK, USBHS_HSTPIPCFGx.PSIZE, USBHS_HSTPIPCFGx.PTOKEN, USBHS_HSTPIPCFGx.PTYPE, USBHS_HSTPIPCFGx.PEPNUM, USBHS_HSTPIPCFGx.INTFRQ) and its Data Toggle Sequence field (USBHS_HSTPIPISRx.DTSEQ).

The pipe configuration remains active and the pipe is still enabled.

The pipe reset may be associated with a clear of the data toggle sequence. This can be achieved by setting the Reset Data Toggle bit in the Pipe x Control register (USBHS_HSTPIPIMRx.RSTDT) (by writing a one to the Reset Data Toggle Set bit in the Pipe x Control Set register (USBHS_HSTPIPIERx.RSTDTS)).

In the end, the user has to write a zero to the USBHS_HSTPIP.PRSTx bit to complete the reset operation and to start using the FIFO.