embeddedsw/XilinxProcessorIPLib/drivers/gpio/examples/xgpio_example.c

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/*****************************************************************************/
/**
* @file xgpio_example.c
*
* This file contains a design example using the GPIO driver (XGpio) and hardware
* device.  It only uses a channel 1 of a GPIO device.
*
* This example can be ran on the Xilinx ML300 board using the Prototype Pins &
* LEDs of the board connected to the GPIO.
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver   Who  Date     Changes
* ----- ---- -------- -----------------------------------------------
* 1.00a rmm  03/13/02 First release
* 1.00a rpm  08/04/03 Removed second example and invalid macro calls
* 2.00a jhl  12/15/03 Added support for dual channels
* 2.00a sv   04/20/05 Minor changes to comply to Doxygen and coding guidelines
* 3.00a ktn  11/20/09 Minor changes as per coding guidelines.
*
* </pre>
******************************************************************************/

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

#include "xparameters.h"
#include "xgpio.h"


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

#define LED 0x01   /* Assumes bit 0 of GPIO is connected to an LED  */

/*
 * The following constant maps to the name of the hardware instances that
 * were created in the EDK XPS system.
 */
#define GPIO_EXAMPLE_DEVICE_ID  XPAR_LEDS_POSITIONS_DEVICE_ID

/*
 * The following constant is used to wait after an LED is turned on to make
 * sure that it is visible to the human eye.  This constant might need to be
 * tuned for faster or slower processor speeds.
 */
#define LED_DELAY     1000000

/*
 * The following constant is used to determine which channel of the GPIO is
 * used for the LED if there are 2 channels supported.
 */
#define LED_CHANNEL 1

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


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

#ifdef PRE_2_00A_APPLICATION

/*
 * The following macros are provided to allow an application to compile that
 * uses an older version of the driver (pre 2.00a) which did not have a channel
 * parameter. Note that the channel parameter is fixed as channel 1.
 */
#define XGpio_SetDataDirection(InstancePtr, DirectionMask) \
        XGpio_SetDataDirection(InstancePtr, LED_CHANNEL, DirectionMask)

#define XGpio_DiscreteRead(InstancePtr) \
        XGpio_DiscreteRead(InstancePtr, LED_CHANNEL)

#define XGpio_DiscreteWrite(InstancePtr, Mask) \
        XGpio_DiscreteWrite(InstancePtr, LED_CHANNEL, Mask)

#define XGpio_DiscreteSet(InstancePtr, Mask) \
        XGpio_DiscreteSet(InstancePtr, LED_CHANNEL, Mask)

#endif

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


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

/*
 * The following are declared globally so they are zeroed and so they are
 * easily accessible from a debugger
 */

XGpio Gpio; /* The Instance of the GPIO Driver */

/*****************************************************************************/
/**
*
* The purpose of this function is to illustrate how to use the GPIO level 1
* driver to turn on and off an LED.
*
* @param	None
*
* @return	XST_FAILURE to indicate that the GPIO Intialisation had failed.
*
* @note		This function will not return if the test is running.
*
******************************************************************************/
int main(void)
{
	u32 Data;
	int Status;
	volatile int Delay;

	/*
	 * Initialize the GPIO driver
	 */
	Status = XGpio_Initialize(&Gpio, GPIO_EXAMPLE_DEVICE_ID);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}

	/*
	 * Set the direction for all signals to be inputs except the
	 * LED output
	 */
	XGpio_SetDataDirection(&Gpio, LED_CHANNEL, ~LED);

	/* Loop forever blinking the LED */

	while (1) {
		/*
		 * Read the state of the data so that only the LED state can be
		 * modified
		 */
		Data = XGpio_DiscreteRead(&Gpio, LED_CHANNEL);

		/*
		 * Set the LED to the opposite state such that it blinks using
		 * the first method, two methods are used for illustration
		 * purposes only
		 */
		if (Data & LED) {
			XGpio_DiscreteWrite(&Gpio, LED_CHANNEL, Data & ~LED);
		} else {
			XGpio_DiscreteWrite(&Gpio, LED_CHANNEL, Data | LED);
		}

		/* Wait a small amount of time so the LED is visible */

		for (Delay = 0; Delay < LED_DELAY; Delay++);

		/*
		 * Read the state of the data so that only the LED state can be
		 * modified
		 */
		Data = XGpio_DiscreteRead(&Gpio, LED_CHANNEL);

		/*
		 * Set the LED to the opposite state such that it blinks using
		 * the other API functions
		 */
		if (Data & LED) {
			XGpio_DiscreteClear(&Gpio, LED_CHANNEL, LED);
		} else {
			XGpio_DiscreteSet(&Gpio, LED_CHANNEL, LED);
		}

		/* Wait a small amount of time so the LED is visible */

		for (Delay = 0; Delay < LED_DELAY; Delay++);
	}

	return XST_SUCCESS;
}