TMS320F28379D: [FAQ] TMS320F28379D: Problems with usb lib using

chang lianqing

Part Number: TMS320F28379D
Other Parts Discussed in Thread: C2000WARE

hello,

QUESTION: when usb CDC device interrupt program has been triggered and USB_EVENT_RX_AVAILABLE is obtained.

The return value of USBDCDCRxPacketAvailable(&g_sCDCDevice) has always been 0.

I'm sure get the data, because of i get the correct data by USBBufferRead(const tUSBBuffer *psBuffer, uint8_t *pui8Data, uint32_t ui32Length)

Please help analyze what went wrong. thank you.

uint32_t RxHandler(void *pvCBData, uint32_t ui32Event, uint32_t ui32MsgValue, void *pvMsgData)
{

    switch(ui32Event)
    {
        //
        // A new packet has been received.
        //
        case USB_EVENT_RX_AVAILABLE:
        {
            uint32_t rx_available = USBDCDCRxPacketAvailable(&g_sCDCDevice);
            break;
        }

case USB_EVENT_DATA_REMAINING:
{

            uint32_t rx_available = USBDCDCRxPacketAvailable(&g_sCDCDevice);

            return(0);
}

        case USB_EVENT_REQUEST_BUFFER:
        {
            return(0);
        }

        //
        // We don't expect to receive any other events. Ignore any that show
        // up in a release build or hang in a debug build.
        //
        default:
#ifdef DEBUG
            while(1);
#else
            break;
#endif
    }

return(0);
}

over 5 years ago

0 Kevin Allen18 over 5 years ago

TI__Mastermind 45606 points

Hi Chang,

To debug this further you can dig into the USB library source code located at the below directory. You can import the project into CCS and I think you can even place breakpoints within it to further debug the 'USBDCDCRxPacketAvailable' function during run time. You may need to link the library in a different way to do this however.

C:\ti\c2000\C2000Ware_2_01_00_00\libraries\communications\usb\f2837xd

Please see the possible ways the function can return 0 per the below function source code.

//*****************************************************************************
//
//! Determines whether a packet is available and, if so, the size of the
//! buffer required to read it.
//!
//! \param pvCDCDevice is the pointer to the device instance structure as
//! returned by USBDCDCInit().
//!
//! This function may be used to determine if a received packet remains to be
//! read and allows the application to determine the buffer size needed to
//! read the data.
//!
//! \return Returns 0 if no received packet remains unprocessed or the
//! size of the packet if a packet is waiting to be read.
//
//*****************************************************************************
uint32_t
USBDCDCRxPacketAvailable(void *pvCDCDevice)
{
    uint32_t ui32EPStatus, ui32Size;
    tCDCSerInstance *psInst;

    ASSERT(pvCDCDevice);

    //
    // Get a pointer to the CDC device instance data pointer
    //
    psInst = &((tUSBDCDCDevice *)pvCDCDevice)->sPrivateData;

    //
    // If receive is currently blocked, return 0.
    //
    if(psInst->bRxBlocked || psInst->bControlBlocked)
    {
        return(0);
    }

    //
    // Does the relevant endpoint FIFO have a packet waiting for us?
    //
    ui32EPStatus = USBEndpointStatus(psInst->ui32USBBase,
                                     psInst->ui8BulkOUTEndpoint);

    if(ui32EPStatus & USB_DEV_RX_PKT_RDY)
    {
        //
        // Yes - a packet is waiting.  How big is it?
        //
        ui32Size = USBEndpointDataAvail(psInst->ui32USBBase,
                                        psInst->ui8BulkOUTEndpoint);

        return(ui32Size);
    }
    else
    {
        //
        // There is no packet waiting to be received.
        //
        return(0);
    }
}

Best,

Kevin

0 chang lianqing over 5 years ago in reply to Kevin Allen18

Intellectual 770 points

Hi Kevin，

thank you,

i had place breakpoints within the function, and USBEndpointStatus() never return USB_DEV_RX_PKT_RDY.

28379's usb send data to PC COM is OK by USBDCDCPacketWrite().

when PC send data to 28379 via COM , Data can only be read out through USBBufferRead(const tUSBBuffer *psBuffer, uint8_t *pui8Data, uint32_t ui32Length)

so, I guess the problem is that the virtual serial port is used as USB communication on my PC, so the endpoint's end state is not obtained.?

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TMS320F28379D: [FAQ] TMS320F28379D: Problems with usb lib using