GPIO_Zynq7020

It is a simplified GPIO interrupt example for Xilinx ZYNQ FPGA. I want to explain each function in this code what it can do.

first of all, we have 2 subfunctions and 1 main:

• GPIOIntrHandler
• SetupInterruptSystem
• main

in the Mian part, we have this code:

int main() {

XGpioPs_Config *GPIOConfigPtr;

init_platform();

GPIOConfigPtr = XGpioPs_LookupConfig(XPAR_XGPIOPS_0_DEVICE_ID);

XGpioPs_CfgInitialize(&xGpioPs, GPIOConfigPtr,GPIOConfigPtr->BaseAddr);

XGpioPs_SetDirectionPin(&xGpioPs, pbsw, 0);

SetupInterruptSystem(&xscugic, &xGpioPs, XPS_GPIO_INT_ID);

XGpioPs_SetDirectionPin(&xGpioPs, ledpin, 1);

XGpioPs_SetOutputEnablePin(&xGpioPs, ledpin, 1);

while(1){ }

}

now let me tell you what was it.

• GPIOConfigPtr = XGpioPs_LookupConfig(XPAR_XGPIOPS_0_DEVICE_ID);

• XGpioPs_CfgInitialize(&xGpioPs, GPIOConfigPtr,GPIOConfigPtr->BaseAddr);

these lines are definitions of GPIO Config that we want to use.

in this simplified example we have 2 pins as GPIO: One for Input, One for Output.

• XGpioPs_SetDirectionPin()

This function, use for showing which pis is Ip=nput and which pin is output and for this aim we use it.

• SetupInterruptSystem()

  this function is for activation of interrupt of the system and it contains several functions for init interrupt of GPIO. this function contains:

  	static void SetupInterruptSystem(XScuGic *XScuGicptr, XGpioPs *xgpiops, u16 GpioIntrId)
  	{  
    
    XScuGic_Config *IntcConfig;
  
    Xil_ExceptionInit();
  
    IntcConfig = XScuGic_LookupConfig(XPAR_SCUGIC_SINGLE_DEVICE_ID);
  
    XScuGic_CfgInitialize(XScuGicptr, IntcConfig,IntcConfig->CpuBaseAddress);
  
    Xil_ExceptionRegisterHandler(XIL_EXCEPTION_ID_INT,(Xil_ExceptionHandler)XScuGic_InterruptHandler,XScuGicptr);
  
    XScuGic_Connect(XScuGicptr, GpioIntrId,(Xil_ExceptionHandler)XGpioPs_IntrHandler,(void *)xgpiops);
  
  
    XGpioPs_SetIntrTypePin(xgpiops, pbsw, XGPIOPS_IRQ_TYPE_EDGE_RISING);
  
    XGpioPs_SetCallbackHandler(&xgpiops, (void *)xgpiops, GPIOIntrHandler);
  
    XGpioPs_IntrEnablePin(xgpiops, pbsw);
  
    XScuGic_Enable(XScuGicptr, GpioIntrId);
  
    Xil_ExceptionEnableMask(XIL_EXCEPTION_IRQ);
  

  }

in my code, I want to use a pin as Input that when changing the state of this pin calls a function with the name of XGpioPs_IntrHandler.

• XGpioPs_SetOutputEnablePin

  This function is used for setting the Output Enables of all the pins in the specified bank.

• XGpioPs_IntrHandler

  This function is used to toggle the state of our led pin.

Please don’t hesitate to contact me for any further assistance.

Saeid Safari Abrazi

Abrazi.saeid@gmail.com