/**
*
* 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)
{
u8 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;
}
}
/* 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;
return ReceivedCount;
}
/**
*
* 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;
}
