embeddedsw/XilinxProcessorIPLib/drivers/uartlite/examples/xuartlite_polled_example.c

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/******************************************************************************/
/**
*
* @file xuartlite_polled_example.c
*
* This file contains a design example using the UartLite driver (XUartLite) and
* hardware device using the polled mode.
*
* @note
*
* The user must provide a physical loopback such that data which is
* transmitted will be received.
*
* MODIFICATION HISTORY:
* <pre>
* Ver   Who  Date	 Changes
* ----- ---- -------- -----------------------------------------------
* 1.00a jhl  02/13/02 First release
* 1.00a sv   06/13/05 Minor changes to comply to Doxygen and coding guidelines
* 2.00a ktn  10/20/09 Updated this example to wait for valid data in receive
*		      fifo instead of Tx fifo empty to update receive buffer
*		      and minor changes as per coding guidelines.
* </pre>
******************************************************************************/

/***************************** Include Files *********************************/

#include "xparameters.h"
#include "xstatus.h"
#include "xuartlite.h"

/************************** Constant Definitions *****************************/

/*
 * The following constants map to the XPAR parameters created in the
 * xparameters.h file. They are defined here such that a user can easily
 * change all the needed parameters in one place.
 */
#define UARTLITE_DEVICE_ID	XPAR_UARTLITE_0_DEVICE_ID

/*
 * The following constant controls the length of the buffers to be sent
 * and received with the UartLite, this constant must be 16 bytes or less since
 * this is a single threaded non-interrupt driven example such that the
 * entire buffer will fit into the transmit and receive FIFOs of the UartLite.
 */
#define TEST_BUFFER_SIZE 16

/**************************** Type Definitions *******************************/


/***************** Macros (Inline Functions) Definitions *********************/


/************************** Function Prototypes ******************************/

int UartLitePolledExample(u16 DeviceId);

/************************** Variable Definitions *****************************/

XUartLite UartLite;		/* Instance of the UartLite Device */

/*
 * The following buffers are used in this example to send and receive data
 * with the UartLite.
 */
u8 SendBuffer[TEST_BUFFER_SIZE];	/* Buffer for Transmitting Data */
u8 RecvBuffer[TEST_BUFFER_SIZE];	/* Buffer for Receiving Data */

/*****************************************************************************/
/**
*
* Main function to call the Uartlite polled example.
*
* @param	None.
*
* @return	XST_SUCCESS if successful, otherwise XST_FAILURE.
*
* @note		None.
*
******************************************************************************/
int main(void)
{
	int Status;

	/*
	 * Run the UartLite polled example, specify the Device ID that is
	 * generated in xparameters.h
	 */
	Status = UartLitePolledExample(UARTLITE_DEVICE_ID);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}

	return XST_SUCCESS;

}


/****************************************************************************/
/**
* This function does a minimal test on the UartLite device and driver as a
* design example. The purpose of this function is to illustrate
* how to use the XUartLite component.
*
* This function sends data and expects to receive the data thru the UartLite
* such that a  physical loopback must be done with the transmit and receive
* signals of the UartLite.
*
* This function polls the UartLite and does not require the use of interrupts.
*
* @param	DeviceId is the Device ID of the UartLite and is the
*		XPAR_<uartlite_instance>_DEVICE_ID value from xparameters.h.
*
* @return	XST_SUCCESS if successful, XST_FAILURE if unsuccessful.
*
*
* @note
*
* This function calls the UartLite driver functions in a blocking mode such that
* if the transmit data does not loopback to the receive, this function may
* not return.
*
****************************************************************************/
int UartLitePolledExample(u16 DeviceId)
{
	int Status;
	unsigned int SentCount;
	unsigned int ReceivedCount = 0;
	int Index;

	/*
	 * Initialize the UartLite driver so that it is ready to use.
	 */
	Status = XUartLite_Initialize(&UartLite, DeviceId);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}

	/*
	 * Perform a self-test to ensure that the hardware was built correctly.
	 */
	Status = XUartLite_SelfTest(&UartLite);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}

	/*
	 * Initialize the send buffer bytes with a pattern to send and the
	 * the receive buffer bytes to zero.
	 */
	for (Index = 0; Index < TEST_BUFFER_SIZE; Index++) {
		SendBuffer[Index] = Index;
		RecvBuffer[Index] = 0;
	}

	/*
	 * Send the buffer through the UartLite waiting til the data can be sent
	 * (block), if the specified number of bytes was not sent successfully,
	 * then an error occurred.
	 */
	SentCount = XUartLite_Send(&UartLite, SendBuffer, TEST_BUFFER_SIZE);
	if (SentCount != TEST_BUFFER_SIZE) {
		return XST_FAILURE;
	}

	/*
	 * Receive the number of bytes which is transfered.
	 * Data may be received in fifo with some delay hence we continuously
	 * check the receive fifo for valid data and update the receive buffer
	 * accordingly.
	 */
	while (1) {
		ReceivedCount += XUartLite_Recv(&UartLite,
					   RecvBuffer + ReceivedCount,
					   TEST_BUFFER_SIZE - ReceivedCount);
		if (ReceivedCount == TEST_BUFFER_SIZE) {
			break;
		}
	}

	/*
	 * Check the receive buffer data against the send buffer and verify the
	 * data was correctly received.
	 */
	for (Index = 0; Index < TEST_BUFFER_SIZE; Index++) {
		if (SendBuffer[Index] != RecvBuffer[Index]) {
			return XST_FAILURE;
		}
	}

	return XST_SUCCESS;
}