38.6.3.11 Management of OUT Pipes
OUT packets are sent by the host. All data which acknowledges or not the bank can be written when it is full.
The pipe must be configured and unfrozen first.
The Transmitted OUT Data Interrupt (USBHS_HSTPIPISRx.TXOUTI) bit is set at the same time as USBHS_HSTPIPIMRx.FIFOCON when the current bank is free. This triggers a PEP_x interrupt if the Transmitted OUT Data Interrupt Enable (USBHS_HSTPIPIMRx.TXOUTE) bit is one.
USBHS_HSTPIPISRx.TXOUTI is cleared by software (by writing a one to the Transmitted OUT Data Interrupt Clear (USBHS_HSTPIPIDRx.TXOUTIC) bit to acknowledge the interrupt, which has no effect on the pipe FIFO.
The user then writes into the FIFO and clears the USBHS_HSTPIPIDRx.FIFOCON bit to allow the USBHS to send the data. If the OUT pipe is composed of multiple banks, this also switches to the next bank. The USBHS_HSTPIPISRx.TXOUTI and USBHS_HSTPIPIMRx.FIFOCON bits are updated in accordance with the status of the next bank.
USBHS_HSTPIPISRx.TXOUTI is always cleared before clearing USBHS_HSTPIPIMRx.FIFOCON.
The USBHS_HSTPIPISRx.RWALL bit is set when the current bank is not full, i.e., when the software can write further data into the FIFO.
- If the user decides to switch to the Suspend state (by writing a zero to the USBHS_HSTCTRL.SOFE bit) while a bank is ready to be sent, the USBHS automatically exits this state and the bank is sent.
- In High-speed operating mode, the host controller automatically manages the PING protocol to maximize the USB bandwidth. The user can tune the PING protocol by handling the Ping Enable (PINGEN) bit and the bInterval Parameter for the Bulk-Out/Ping Transaction (BINTERVAL) field in USBHS_HSTPIPCFGx. See the Host Pipe x Configuration Register for additional information.
