77.PS接收来自PL的按键中断

本篇文章主要介绍外设（PL）产生的中断请求，在PS端进行处理。 
在PL端通过按键产生中断，PS接受到之后点亮相应的LED.

本文所使用的开发板是zedboard
PC 开发环境版本：Vivado 2015.4 Xilinx SDK 2015.4

搭建硬件工程

建好工程后，添加ZYNQ IP

双击 ZYNQ,打开Re-customize IP对话框，使能IRQ_P2P

使能UART1

点击Run Connection Automation,按照如图所示配置，点击OK

添加一个GPIO IP,按照如图所示配置，使能中断。点击Run Connection Automation

再添加一个GPIO IP，按照如图所示配置,点击OK

把axi_gpio_0的ip2intc_irpt和ZYNQ PS的 IRQ_F2P[0:0]连在一起

搭建好的硬件系统连接，如图所示

生成顶层文件，点击Generate BitStream

软件工程

新建一个Hello World工程，把以下代码添加进去

  1 #include <stdio.h>
  2 #include "platform.h"
  3 #include "xparameters.h"
  4 #include "xscugic.h"
  5 #include "xil_exception.h"
  6 #include "xgpio.h"
  7
  8 //parameter definitions
  9 #define INTC_DEVICE_ID    XPAR_PS7_SCUGIC_0_DEVICE_ID  //DEVICE_ID用来初始化函数，索引数组元素
 10 #define LED_DEVICE_ID     XPAR_AXI_GPIO_1_DEVICE_ID
 11 #define BTNS_DEVICE_ID    XPAR_AXI_GPIO_0_DEVICE_ID
 12 #define INTC_GPIO_INTERRUPT_ID    XPAR_FABRIC_AXI_GPIO_0_IP2INTC_IRPT_INTR
 13 #define BTN_INT    XGPIO_IR_CH1_MASK
 14 #define DELAY 100000000
 15
 16 XGpio LED;
 17 XGpio BTNInst;
 18 XScuGic    INTCInst;
 19 static int btn_value;
 20
 21 //Function protype
 22 static void BTN_Intr_Handler(void *baseaddr_p);
 23 static int InterruptSystemSetup(XScuGic *XScuGicInstancePtr);
 24 static int IntcInitFunction(u16 DeviceId,XGpio *GpioInstancePtr);
 25
 26 void BTN_Intr_Handler(void *InstancePtr)
 27 {
 28     unsigned char led_val=0;
 29     //Ignore additional button presses
 30     if((XGpio_InterruptGetStatus(&BTNInst) & BTN_INT) != BTN_INT)
 31     {
 32         return;
 33         //Disable GPIO interrupts
 34         XGpio_InterruptDisable(&BTNInst,BTN_INT);
 35     }
 36     btn_value = XGpio_DiscreteRead(&BTNInst,1);
 37     switch(btn_value)
 38     {
 39     case 1: led_val = 0x01;break;  //led[7:0]=0x01
 40     case 2:    led_val = 0x02;break;
 41     case 4:    led_val = 0x03;break; //亮1和2
 42     case 8:    led_val = 0x04;break;
 43     case 16:   led_val = 0x05;break; //亮0和2
 44     default:break;
 45     }
 46
 47     XGpio_DiscreteWrite(&LED,1,led_val);
 48     //Acknowledge GPIO interrupts
 49     (void)XGpio_InterruptClear(&BTNInst,BTN_INT);
 50     //Enable GPIO interrupts
 51     XGpio_InterruptEnable(&BTNInst,BTN_INT);
 52 }
 53
 54 int main(void)
 55 {
 56     int status;
 57
 58     //按键初始化
 59     status = XGpio_Initialize(&BTNInst,BTNS_DEVICE_ID);
 60     if(status != XST_SUCCESS) return XST_FAILURE;
 61
 62     //初始化LED
 63     status = XGpio_Initialize(&LED,LED_DEVICE_ID);
 64     if(status != XST_SUCCESS) return XST_FAILURE;
 65
 66     //设置按键IO的方向为输入
 67     XGpio_SetDataDirection(&BTNInst,1,0xff);
 68     //设置LED IO 的方向为输出
 69     XGpio_SetDataDirection(&LED,1,0X00);
 70
 71     //初始化中断控制器
 72     status = IntcInitFunction(INTC_DEVICE_ID,&BTNInst);
 73     if(status != XST_SUCCESS) return XST_FAILURE;
 74
 75     while(1){}
 76
 77     return 0;
 78 }
 79
 80 int IntcInitFunction(u16 DeviceId,XGpio *GpioInstancePtr)
 81 {
 82     XScuGic_Config *IntcConfig;
 83     int status;
 84
 85     //Interrupt controller initialization
 86     IntcConfig = XScuGic_LookupConfig(DeviceId);
 87     status = XScuGic_CfgInitialize(&INTCInst,IntcConfig,IntcConfig->CpuBaseAddress);
 88     if(status != XST_SUCCESS) return XST_FAILURE;
 89
 90     //Call interrupt setup function
 91     status = InterruptSystemSetup(&INTCInst);
 92     if(status != XST_SUCCESS) return XST_FAILURE;
 93
 94     //Register GPIO interrupt handler
 95     status = XScuGic_Connect(&INTCInst,INTC_GPIO_INTERRUPT_ID,(Xil_ExceptionHandler)BTN_Intr_Handler,(void *)GpioInstancePtr);
 96     if(status != XST_SUCCESS) return XST_FAILURE;
 97
 98     //Enable GPIO interrupts
 99     XGpio_InterruptEnable(GpioInstancePtr,1);
100     XGpio_InterruptGlobalEnable(GpioInstancePtr);
101
102     //Enable GPIO interrupts in the controller
103     XScuGic_Enable(&INTCInst,INTC_GPIO_INTERRUPT_ID);
104
105     return XST_SUCCESS;
106 }
107
108 int InterruptSystemSetup(XScuGic *XScuGicInstancePtr)
109 {
110     //Register GIC interrupt handler
111     Xil_ExceptionRegisterHandler(XIL_EXCEPTION_ID_INT,(Xil_ExceptionHandler)XScuGic_InterruptHandler,XScuGicInstancePtr);
112     Xil_ExceptionEnable();
113
114     return XST_SUCCESS;
115 }

下载好之后，按键按下可以看到相应的LED被点亮