2x1=10

Just a quick and dirty non-tuto­r­i­al solu­tion on how to use the mul­ti­plexed I/Os (MIO/GPIO) to wire the BTN4 but­ton on the ZYBO board (MIO50, the right one) to the LD4 LED (MIO7). Both are con­nect­ed direct­ly to the pro­cess­ing sys­tem and can­not be con­trolled from the fab­ric.

#include "platform.h"

#include "xparameters.h"
#include "xgpiops.h"
#include "xstatus.h"

#define GPIO_DEVICE_ID  XPAR_XGPIOPS_0_DEVICE_ID
#define OUTPUT_PIN		7	/* MIO7,  pin connected to LED */
#define INPUT_PIN		50	/* MIO50, pin connected to button */

int main()
{
	int Status;
	XGpioPs Gpio;
	XGpioPs_Config *ConfigPtr;

        // Initialize the system
	init_platform();

	// initialize the GPIO driver.
	ConfigPtr = XGpioPs_LookupConfig(GPIO_DEVICE_ID);
	Status = XGpioPs_CfgInitialize(&Gpio, ConfigPtr, ConfigPtr->BaseAddr);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}

	// configure the LED pin as output
	// status checks skipped for readability
	XGpioPs_SetDirectionPin(&Gpio, OUTPUT_PIN, 1);
	XGpioPs_SetOutputEnablePin(&Gpio, OUTPUT_PIN, 1);

	// configure the button pin as input
	XGpioPs_SetDirectionPin(&Gpio, INPUT_PIN, 0);

	// wire the button to the LED (inverted)
	while(1)
	{
		u32 data = XGpioPs_ReadPin(&Gpio, INPUT_PIN);
		XGpioPs_WritePin(&Gpio, OUTPUT_PIN, !data);
	}

    return 0;
}

Note that when you open the system.mss file in SDK, you’ll find the ps7_gpio_0 entry under the Periph­er­al Dri­vers sec­tion. Click “Exam­ple” there to find more infor­ma­tion.