usbctrltrf.c

cpu采用Microchip公司的pic16f4520

 *                  USBCtrlTrfInHandler(). It takes care of managing a
 *                  transfer over multiple USB transactions.
 *
 * Note:            This routine works with isochronous endpoint larger than
 *                  256 bytes and is shown here as an example of how to deal
 *                  with BC9 and BC8. In reality, a control endpoint can never
 *                  be larger than 64 bytes.
 *****************************************************************************/
void USBCtrlTrfTxService(void)
{    
    WORD byte_to_send;
    
    /*
     * First, have to figure out how many byte of data to send.
     */
    if(wCount._word < EP0_BUFF_SIZE)
        byte_to_send._word = wCount._word;
    else
        byte_to_send._word = EP0_BUFF_SIZE;
    
    /*
     * Next, load the number of bytes to send to BC9..0 in buffer descriptor
     */
    ep0Bi.Stat.BC9 = 0;
    ep0Bi.Stat.BC8 = 0;
    ep0Bi.Stat._byte |= MSB(byte_to_send);
    ep0Bi.Cnt = LSB(byte_to_send);
    
    /*
     * Subtract the number of bytes just about to be sent from the total.
     */
    wCount._word = wCount._word - byte_to_send._word;
    
    pDst.bRam = (byte*)&CtrlTrfData;        // Set destination pointer

    if(usb_stat.ctrl_trf_mem == _ROM)       // Determine type of memory source
    {
        while(byte_to_send._word)
        {
            *pDst.bRam = *pSrc.bRom;
            pDst.bRam++;
            pSrc.bRom++;
            byte_to_send._word--;
        }//end while(byte_to_send._word)
    }
    else // RAM
    {
        while(byte_to_send._word)
        {
            *pDst.bRam = *pSrc.bRam;
            pDst.bRam++;
            pSrc.bRam++;
            byte_to_send._word--;
        }//end while(byte_to_send._word)
    }//end if(usb_stat.ctrl_trf_mem == _ROM)
    
}//end USBCtrlTrfTxService

/******************************************************************************
 * Function:        void USBCtrlTrfRxService(void)
 *
 * PreCondition:    pDst and wCount are setup properly.
 *                  pSrc is always &CtrlTrfData
 *                  usb_stat.ctrl_trf_mem is always _RAM.
 *                  wCount should be set to 0 at the start of each control
 *                  transfer.
 *
 * Input:           None
 *
 * Output:          None
 *
 * Side Effects:    None
 *
 * Overview:        *** This routine is only partially complete. Check for
 *                  new version of the firmware.
 *
 * Note:            None
 *****************************************************************************/
void USBCtrlTrfRxService(void)
{
    WORD byte_to_read;

    MSB(byte_to_read) = 0x03 & ep0Bo.Stat._byte;    // Filter out last 2 bits
    LSB(byte_to_read) = ep0Bo.Cnt;
    
    /*
     * Accumulate total number of bytes read
     */
    wCount._word = wCount._word + byte_to_read._word;
    
    pSrc.bRam = (byte*)&CtrlTrfData;

    while(byte_to_read._word)
    {
        *pDst.bRam = *pSrc.bRam;
        pDst.bRam++;
        pSrc.bRam++;
        byte_to_read._word--;
    }//end while(byte_to_read._word)    
    
}//end USBCtrlTrfRxService

/******************************************************************************
 * Function:        void USBCtrlEPServiceComplete(void)
 *
 * PreCondition:    None
 *
 * Input:           None
 *
 * Output:          None
 *
 * Side Effects:    None
 *
 * Overview:        This routine wrap up the ramaining tasks in servicing
 *                  a Setup Request. Its main task is to set the endpoint
 *                  controls appropriately for a given situation. See code
 *                  below.
 *                  There are three main scenarios:
 *                  a) There was no handler for the Request, in this case
 *                     a STALL should be sent out.
 *                  b) The host has requested a read control transfer,
 *                     endpoints are required to be setup in a specific way.
 *                  c) The host has requested a write control transfer, or
 *                     a control data stage is not required, endpoints are
 *                     required to be setup in a specific way.
 *
 *                  Packet processing is resumed by clearing PKTDIS bit.
 *
 * Note:            None
 *****************************************************************************/
void USBCtrlEPServiceComplete(void)
{
    if(ctrl_trf_session_owner == MUID_NULL)
    {
        /*
         * If no one knows how to service this request then stall.
         * Must also prepare EP0 to receive the next SETUP transaction.
         */
        ep0Bo.Cnt = EP0_BUFF_SIZE;
        ep0Bo.ADR = (byte*)&SetupPkt;
        
        ep0Bo.Stat._byte = _USIE|_BSTALL;
        ep0Bi.Stat._byte = _USIE|_BSTALL;
    }
    else    // A module has claimed ownership of the control transfer session.
    {
        if(SetupPkt.DataDir == DEV_TO_HOST)
        {
            if(SetupPkt.wLength < wCount._word)
                wCount._word = SetupPkt.wLength;
            USBCtrlTrfTxService();
            ctrl_trf_state = CTRL_TRF_TX;
            /*
             * Control Read:
             * <SETUP[0]><IN[1]><IN[0]>...<OUT[1]> | <SETUP[0]>
             * 1. Prepare OUT EP to respond to early termination
             *
             * NOTE:
             * If something went wrong during the control transfer,
             * the last status stage may not be sent by the host.
             * When this happens, two different things could happen
             * depending on the host.
             * a) The host could send out a RESET.
             * b) The host could send out a new SETUP transaction
             *    without sending a RESET first.
             * To properly handle case (b), the OUT EP must be setup
             * to receive either a zero length OUT transaction, or a
             * new SETUP transaction.
             *
             * Since the SETUP transaction requires the DTS bit to be
             * DAT0 while the zero length OUT status requires the DTS
             * bit to be DAT1, the DTS bit check by the hardware should
             * be disabled. This way the SIE could accept either of
             * the two transactions.
             *
             * Furthermore, the Cnt byte should be set to prepare for
             * the SETUP data (8-byte or more), and the buffer address
             * should be pointed to SetupPkt.
             */
            ep0Bo.Cnt = EP0_BUFF_SIZE;
            ep0Bo.ADR = (byte*)&SetupPkt;            
            ep0Bo.Stat._byte = _USIE;           // Note: DTSEN is 0!
    
            /*
             * 2. Prepare IN EP to transfer data, Cnt should have
             *    been initialized by responsible request owner.
             */
            ep0Bi.ADR = (byte*)&CtrlTrfData;
            ep0Bi.Stat._byte = _USIE|_DAT1|_DTSEN;
        }
        else    // (SetupPkt.DataDir == HOST_TO_DEV)
        {
            ctrl_trf_state = CTRL_TRF_RX;
            /*
             * Control Write:
             * <SETUP[0]><OUT[1]><OUT[0]>...<IN[1]> | <SETUP[0]>
             *
             * 1. Prepare IN EP to respond to early termination
             *
             *    This is the same as a Zero Length Packet Response
             *    for control transfer without a data stage
             */
            ep0Bi.Cnt = 0;
            ep0Bi.Stat._byte = _USIE|_DAT1|_DTSEN;

            /*
             * 2. Prepare OUT EP to receive data.
             */
            ep0Bo.Cnt = EP0_BUFF_SIZE;
            ep0Bo.ADR = (byte*)&CtrlTrfData;
            ep0Bo.Stat._byte = _USIE|_DAT1|_DTSEN;
        }//end if(SetupPkt.DataDir == DEV_TO_HOST)
    }//end if(ctrl_trf_session_owner == MUID_NULL)
    
    /*
     * PKTDIS bit is set when a Setup Transaction is received.
     * Clear to resume packet processing.
     */
    UCONbits.PKTDIS = 0;

}//end USBCtrlEPServiceComplete

/******************************************************************************
 * Function:        void USBPrepareForNextSetupTrf(void)
 *
 * PreCondition:    None
 *
 * Input:           None
 *
 * Output:          None
 *
 * Side Effects:    None
 *
 * Overview:        The routine forces EP0 OUT to be ready for a new Setup
 *                  transaction, and forces EP0 IN to be owned by CPU.
 *
 * Note:            None
 *****************************************************************************/
void USBPrepareForNextSetupTrf(void)
{
    ctrl_trf_state = WAIT_SETUP;            // See usbctrltrf.h
    ep0Bo.Cnt = EP0_BUFF_SIZE;              // Defined in usbcfg.h
    ep0Bo.ADR = (byte*)&SetupPkt;
    ep0Bo.Stat._byte = _USIE|_DAT0|_DTSEN;  // EP0 buff dsc init, see usbmmap.h
    ep0Bi.Stat._byte = _UCPU;               // EP0 IN buffer initialization
}//end USBPrepareForNextSetupTrf

/** EOF usbctrltrf.c *********************************************************/