CSL USB: Can't retrieve OUT data from the FIFO with USB_postTransaction.

Hi Stefan,

The CCS memory window capture is not the content of the USB EP FIFO. It is the USB EP FIFO registers. for example, 0x8429 is the  FIFO2R1 Transmit and Receive FIFO Register 1 for Endpoint 2. You can read it word by word to get all the contents in the EP FIFO. That is what the USB_handleRx do. What triggers the USB_handleRx is the      (pContext->dwIntSourceL & CSL_USB_RX_INT_EP2)  in usb_isr() via USB_postTransaction(). To make sure you actually get data waiting in the EP2, you can add the following code before USB_postTransaction() in usb_isr():

   // read the RX packet size
   // validate the RX packet first
   if (USB_isValidDataInFifoOut(&pContext->pEpStatus[CSL_USB_EP2]))
   {
    // get the EP2 handle
    tempEpH = USB_epNumToHandle(CSL_USB0, CSL_USB_EP2);
    usb_income_num_bytes = USB_getDataCountReadFromFifo( tempEpH );
   }    

 to get the data waiting in the EP2 FIFO in terms of bytes.

After calling USB_postTransaction(), the calling to USB_isTransactionDone() will tell you the status of this operation. If everything is OK, then you should have the data in usbDataBuffer.

If you did not get what you suppose to get, it could be the USB host program is not doing the right thing. Here are some possibilities:

1. The host program is sending data in packet size bigger than 64 bytes at a time

2. the host program is sending data to EPs other than EP2 (EP1 for IN and EP2 for OUT)

Best regards,

Ming