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/*****************************************************************************/
/**
* @file xgpio_low_level_example.c
*
* This file contains a design example using the General Purpose I/O (GPIO) low
* level driver and hardware device. It only uses a channel 1 of a GPIO device.
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver   Who  Date	 Changes
* ----- ---- -------- -----------------------------------------------
* 1.00b jhl  04/29/02 First release
* 2.00a jhl  12/30/02 Addition of dual channel capability
* 2.00a sv   04/18/05 Minor changes to comply to Doxygen and coding guidelines
* 3.00a ktn  11/21/09 Removed the macros XGpio_mSetDataDirection,
*		      XGpio_mGetDataReg and XGpio_mSetDataReg. Users
*		      should use XGpio_WriteReg/XGpio_ReadReg to achieve the
*		      same functionality.
* </pre>
*
******************************************************************************/

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

#include "xparameters.h"
#include "xgpio_l.h"

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

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

/*
 * The following constant maps to the Base address  of the hardware
 * instances that was created in the EDK XPS system.
 */
#define GPIO_REG_BASEADDR	XPAR_LEDS_POSITIONS_BASEADDR

/*
 * 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 *********************/


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


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


/*****************************************************************************/
/**
* The purpose of this function is to illustrate how to use the GPIO low level
* driver to turn on and off an LED.
*
* @param	None
*
* @return	Always 0
*
* @note
* The main function is returning an integer to prevent compiler warnings.
*
******************************************************************************/
int main()
{
	u32 Data;
	volatile int Delay;

	/*
	 * Set the direction for all signals to be inputs except the LED output
	 */
	XGpio_WriteReg((GPIO_REG_BASEADDR),
			((LED_CHANNEL - 1) * XGPIO_CHAN_OFFSET) +
			XGPIO_TRI_OFFSET, (~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_ReadReg(GPIO_REG_BASEADDR,
				((LED_CHANNEL - 1) * XGPIO_CHAN_OFFSET) +
				  XGPIO_DATA_OFFSET);


		/* Set the LED to the opposite state such that it blinks */

		if (Data & LED) {

			XGpio_WriteReg((GPIO_REG_BASEADDR),
				((LED_CHANNEL - 1) * XGPIO_CHAN_OFFSET) +
				XGPIO_DATA_OFFSET, Data & ~LED);

		} else {

			XGpio_WriteReg((GPIO_REG_BASEADDR),
				((LED_CHANNEL - 1) * XGPIO_CHAN_OFFSET) +
				XGPIO_DATA_OFFSET, Data | LED);
		}

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

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

	return 0;
}