** None.** @note** None.******************************************************************************/void XUartLite_ResetFifos(XUartLite *InstancePtr){    Xuint32 Register;    XASSERT_VOID(InstancePtr != XNULL);    XASSERT_VOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);    /* Read the status register 1st such that the next write to the control     * register won't destroy the state of the interrupt enable bit     */    Register =        XIo_In32(InstancePtr->RegBaseAddress + XUL_STATUS_REG_OFFSET);    /*     * Mask off the interrupt enable bit to maintain it's state.     */    Register &= XUL_SR_INTR_ENABLED;    /* Write to the control register to reset both FIFOs, these bits are     * self-clearing such that there's no need to clear them     */    XIo_Out32(InstancePtr->RegBaseAddress + XUL_CONTROL_REG_OFFSET,              Register | XUL_CR_FIFO_TX_RESET | XUL_CR_FIFO_RX_RESET);}/****************************************************************************//**** This function determines if the specified UART is sending data. If the* transmitter register is not empty, it is sending data.** @param    InstancePtr is a pointer to the XUartLite instance to be worked on.** @return** A value of XTRUE if the UART is sending data, otherwise XFALSE.** @note** None.******************************************************************************/Xboolean XUartLite_IsSending(XUartLite *InstancePtr){    Xuint32 StatusRegister;    /*     * Assert validates the input arguments     */    XASSERT_NONVOID(InstancePtr != XNULL);    /* Read the status register to determine if the transmitter is     * empty     */    StatusRegister = XIo_In32(InstancePtr->RegBaseAddress + XUL_STATUS_REG_OFFSET);    /* If the transmitter is not empty then indicate that the UART is still     * sending some data     */    return ((StatusRegister & XUL_SR_TX_FIFO_EMPTY) == 0);}/****************************************************************************** This function provides a stub handler such that if the application does not* define a handler but enables interrupts, this function will be called.** @param    CallBackRef has no purpose but is necessary to match the*           interface for a handler.* @param    ByteCount has no purpose but is necessary to match the*           interface for a handler.** @return** None.** @note** None.******************************************************************************/static void StubHandler(void *CallBackRef, unsigned int ByteCount){    /*     * Assert occurs always since this is a stub and should never be called     */    XASSERT_VOID_ALWAYS();}/****************************************************************************** Looks up the device configuration based on the unique device ID.  The table* UartliteConfigTable contains the configuration info for each device in the* system.** @param DeviceId is the unique device ID to match on.** @return** A pointer to the configuration data for the device, or XNULL if no match* was found.** @note** None.*******************************************************************************/XUartLite_Config *XUartLite_LookupConfig(Xuint16 DeviceId){    XUartLite_Config *CfgPtr = XNULL;    int i;    for (i=0; i < XPAR_XUARTLITE_NUM_INSTANCES; i++)    {        if (XUartLite_ConfigTable[i].DeviceId == DeviceId)        {            CfgPtr = &XUartLite_ConfigTable[i];            break;        }    }    return CfgPtr;}/****************************************************************************//**** This function sends a buffer that has been previously specified by setting* up the instance variables of the instance. This function is designed to be* an internal function for the XUartLite component such that it may be called* from a shell function that sets up the buffer or from an interrupt handler.** This function sends the specified buffer of data to the UART in either* polled or interrupt driven modes. This function is non-blocking such that* it will return before the data has been sent by the UART.** In a polled mode, this function will only send as much data as the UART can* buffer, either in the transmitter or in the FIFO if present and enabled.* The application may need to call it repeatedly to send a buffer.** In interrupt mode, this function will start sending the specified buffer and* then the interrupt handler of the driver will continue until the buffer* has been sent. A callback function, as specified by the application, will* be called to indicate the completion of sending the buffer.** @param    InstancePtr is a pointer to the XUartLite instance to be worked on.** @return** NumBytes is the number of bytes actually sent (put into the UART transmitter* and/or FIFO).** @note** None.******************************************************************************/unsigned int XUartLite_SendBuffer(XUartLite *InstancePtr){    unsigned int SentCount = 0;    Xuint32 StatusRegister;    /* Read the line status register to determine if the transmitter is     * full     */    StatusRegister = XUartLite_mGetStatusReg(InstancePtr->RegBaseAddress);    /*     * Fill the FIFO from the the buffer that was specified     */    SentCount = 0;    while (((StatusRegister & XUL_SR_TX_FIFO_FULL) == 0) &&           (SentCount < InstancePtr->SendBuffer.RemainingBytes))    {        XIo_Out32(InstancePtr->RegBaseAddress + XUL_TX_FIFO_OFFSET,                  InstancePtr->SendBuffer.NextBytePtr[SentCount]);        SentCount++;        StatusRegister = XUartLite_mGetStatusReg(InstancePtr->RegBaseAddress);    }    /*     * Update the buffer to reflect the bytes that were sent from it     */    InstancePtr->SendBuffer.NextBytePtr += SentCount;    InstancePtr->SendBuffer.RemainingBytes -= SentCount;    /*     * Increment associated counters     */     InstancePtr->Stats.CharactersTransmitted += SentCount;    /*     * Return the number of bytes that were sent, althought they really were     * only put into the FIFO, not completely sent yet     */    return SentCount;}/****************************************************************************//**** This function receives a buffer that has been previously specified by setting* up the instance variables of the instance. This function is designed to be* an internal function for the XUartLite component such that it may be called* from a shell function that sets up the buffer or from an interrupt handler.** This function will attempt to receive a specified number of bytes of data* from the UART and store it into the specified buffer. This function is* designed for either polled or interrupt driven modes. It is non-blocking* such that it will return if there is no data has already received by the* UART.** In a polled mode, this function will only receive as much data as the UART* can buffer, either in the receiver or in the FIFO if present and enabled.* The application may need to call it repeatedly to receive a buffer. Polled* mode is the default mode of operation for the driver.** In interrupt mode, this function will start receiving and then the interrupt* handler of the driver will continue until the buffer has been received. A* callback function, as specified by the application, will be called to indicate* the completion of receiving the buffer or when any receive errors or timeouts* occur. Interrupt mode must be enabled using the SetOptions function.** @param    InstancePtr is a pointer to the XUartLite instance to be worked on.** @return** The number of bytes received.** @note** None.******************************************************************************/unsigned int XUartLite_ReceiveBuffer(XUartLite *InstancePtr){    Xuint8 StatusRegister;    unsigned int ReceivedCount = 0;    /* Loop until there is not more data buffered by the UART or the specified     * number of bytes is received     */    while (ReceivedCount < InstancePtr->ReceiveBuffer.RemainingBytes)    {        /* Read the Status Register to determine if there is any data in         * the receiver/FIFO         */        StatusRegister = XUartLite_mGetStatusReg(InstancePtr->RegBaseAddress);        /* If there is data ready to be removed, then put the next byte         * received into the specified buffer and update the stats to reflect         * any receive errors for the byte         */        if (StatusRegister & XUL_SR_RX_FIFO_VALID_DATA)        {            InstancePtr->ReceiveBuffer.NextBytePtr[ReceivedCount++] =                XIo_In32(InstancePtr->RegBaseAddress + XUL_RX_FIFO_OFFSET);            XUartLite_mUpdateStats(InstancePtr, StatusRegister);        }        /* There's no more data buffered, so exit such that this function does         * not block waiting for data         */        else        {            break;        }    }    /* Enter a critical region by disabling all the UART interrupts to allow     * this call to stop a previous operation that may be interrupt driven     */    StatusRegister = XUartLite_mGetStatusReg(InstancePtr->RegBaseAddress);    XIo_Out32(InstancePtr->RegBaseAddress + XUL_CONTROL_REG_OFFSET, 0);    /* Update the receive buffer to reflect the number of bytes that was     * received     */    InstancePtr->ReceiveBuffer.NextBytePtr += ReceivedCount;    InstancePtr->ReceiveBuffer.RemainingBytes -= ReceivedCount;    /*     * Increment associated counters in the statistics     */    InstancePtr->Stats.CharactersReceived += ReceivedCount;    /* Restore the interrupt enable register to it's previous value such     * that the critical region is exited     */    StatusRegister &= XUL_CR_ENABLE_INTR;    XIo_Out32(InstancePtr->RegBaseAddress + XUL_CONTROL_REG_OFFSET, StatusRegister);    return ReceivedCount;}