本文详细说明一下使用SDK中使用MIO/EMIO作为输入中断

SDK中使用MIO/EMIO作为输入中断

这个使用场景可以扩展到PL的可以通过EMIO或者MIO，告知PS中断来了，需要PS处理一些特定事物，当然也可以连接最简单的按键。

这个可以参考SDK自带例程来实现需要的功能，通过这个例程实现修改，在SDK中可以这样导入该例程。

 源码分析

这个例程比骄简单，这里仅仅看输入管脚的配置即可，例程中将输入管脚Input_Pin = 14，即使用MIO14作为外部中断输入

首先初始化，初始化使用MIO14，说明使用bank0

Input_Pin = 14;

GPIO的初始化

	/* Initialize the Gpio driver. */
	ConfigPtr = XGpioPs_LookupConfig(DeviceId);
	if (ConfigPtr == NULL) {
		return XST_FAILURE;
	}
	XGpioPs_CfgInitialize(Gpio, ConfigPtr, ConfigPtr->BaseAddr);

	/* Run a self-test on the GPIO device. */
	Status = XGpioPs_SelfTest(Gpio);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}

	/* Set the direction for the specified pin to be input */
	XGpioPs_SetDirectionPin(Gpio, Input_Pin, 0x0);

初始化中断，这里的宏定义GPIO_INTERRUPT_ID就是等于52，也就是GPIO的快速中断号

在著名手册ug585表格7-3中我们可以清晰的看到所有快速中断的编号。

这里有个疑问 MIO/EMIO在Zynq-7000、国产zynq-7000的GPIO控制（一）中一共有118个，怎么找到到底哪个管脚产生了中断呢？？？？？

#define XPS_GPIO_INT_ID            52U

#define XPAR_XGPIOPS_0_INTR        XPS_GPIO_INT_ID

#define GPIO_INTERRUPT_ID    XPAR_XGPIOPS_0_INTR

	/*
	 * Setup the interrupts such that interrupt processing can occur. If
	 * an error occurs then exit.
	 */
	Status = SetupInterruptSystem(Intc, Gpio, GPIO_INTERRUPT_ID);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}

针对这个中断配置函数详细分析，这个函数的详细代码如下

刚开始调用的几个函数，都是对中断的初始化

Xil_ExceptionInit

XScuGic_LookupConfig

XScuGic_CfgInitialize

Xil_ExceptionRegisterHandler

XScuGic_Connect

这里最关键关键是GPIO_BANK，需要根据自己使用的GPIO BANK进行修改，如果不知道gpio在哪个bank，参考《Zynq-7000、国产zynq-7000的GPIO控制（一）》

初始化配置的中断输入管脚是Input_Pin = 14;

所以

#define XGPIOPS_BANK0            0x00U  /**< GPIO Bank 0 */

#define GPIO_BANK    XGPIOPS_BANK0  /* Bank 0 of the GPIO Device */

如果需要配置成其他管脚，一定要修改这里的BANK定义

其中配置中断类型函数

XGpioPs_SetIntrType

这里配置bank0，第三个参数表示中断类型，代码中采用上升沿
#define XGPIOPS_IRQ_TYPE_EDGE_RISING    0x00U  /**< Interrupt on Rising edge */
#define XGPIOPS_IRQ_TYPE_EDGE_FALLING    0x01U  /**< Interrupt Falling edge */
#define XGPIOPS_IRQ_TYPE_EDGE_BOTH    0x02U  /**< Interrupt on both edges */
#define XGPIOPS_IRQ_TYPE_LEVEL_HIGH    0x03U  /**< Interrupt on high level */
#define XGPIOPS_IRQ_TYPE_LEVEL_LOW    0x04U  /**< Interrupt on low level */

这里注册中断处理函数

    /* Set the handler for gpio interrupts. */
    XGpioPs_SetCallbackHandler(Gpio, (void *)Gpio, IntrHandler);

这里使能对应管脚的中断，这个偏移量，也要根据自己的中断引脚做修改

    /* Enable the GPIO interrupts of Bank 0. */
    XGpioPs_IntrEnable(Gpio, GPIO_BANK, (1 << Input_Pin));

/*****************************************************************************/
/**
*
* This function sets up the interrupt system for the example. It enables falling
* edge interrupts for all the pins of bank 0 in the GPIO device.
*
* @param	GicInstancePtr is a pointer to the XScuGic driver Instance.
* @param	GpioInstancePtr contains a pointer to the instance of the GPIO
*		component which is going to be connected to the interrupt
*		controller.
* @param	GpioIntrId is the interrupt Id and is typically
*		XPAR_<GICPS>_<GPIOPS_instance>_VEC_ID value from
*		xparameters.h.
*
* @return	XST_SUCCESS if successful, otherwise XST_FAILURE.
*
* @note		None.
*
****************************************************************************/
static int SetupInterruptSystem(XScuGic *GicInstancePtr, XGpioPs *Gpio,
				u16 GpioIntrId)
{
	int Status;

	XScuGic_Config *IntcConfig; /* Instance of the interrupt controller */

	Xil_ExceptionInit();

	/*
	 * Initialize the interrupt controller driver so that it is ready to
	 * use.
	 */
	IntcConfig = XScuGic_LookupConfig(INTC_DEVICE_ID);
	if (NULL == IntcConfig) {
		return XST_FAILURE;
	}

	Status = XScuGic_CfgInitialize(GicInstancePtr, IntcConfig,
					IntcConfig->CpuBaseAddress);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}


	/*
	 * Connect the interrupt controller interrupt handler to the hardware
	 * interrupt handling logic in the processor.
	 */
	Xil_ExceptionRegisterHandler(XIL_EXCEPTION_ID_INT,
				(Xil_ExceptionHandler)XScuGic_InterruptHandler,
				GicInstancePtr);

	/*
	 * Connect the device driver handler that will be called when an
	 * interrupt for the device occurs, the handler defined above performs
	 * the specific interrupt processing for the device.
	 */
	Status = XScuGic_Connect(GicInstancePtr, GpioIntrId,
				(Xil_ExceptionHandler)XGpioPs_IntrHandler,
				(void *)Gpio);
	if (Status != XST_SUCCESS) {
		return Status;
	}

	/* Enable falling edge interrupts for all the pins in bank 0. */
	XGpioPs_SetIntrType(Gpio, GPIO_BANK, 0x00, 0xFFFFFFFF, 0x00);

	/* Set the handler for gpio interrupts. */
	XGpioPs_SetCallbackHandler(Gpio, (void *)Gpio, IntrHandler);


	/* Enable the GPIO interrupts of Bank 0. */
	XGpioPs_IntrEnable(Gpio, GPIO_BANK, (1 << Input_Pin));


	/* Enable the interrupt for the GPIO device. */
	XScuGic_Enable(GicInstancePtr, GpioIntrId);


	/* Enable interrupts in the Processor. */
	Xil_ExceptionEnableMask(XIL_EXCEPTION_IRQ);

	return XST_SUCCESS;
}

中断处理函数

由于采用上升沿触发中断的方式，这里进入中断处理函数，读取一下中断管脚的值，看看是否为高电平，如果为高电平说明是有效触发。

/****************************************************************************/
/**
* This function is the user layer callback function for the bank 0 interrupts of
* the GPIO device. It checks if all the switches have been pressed to stop the
* interrupt processing and exit from the example.
*
* @param	CallBackRef is a pointer to the upper layer callback reference.
* @param	Status is the Interrupt status of the GPIO bank.
*
* @return	None.
*
* @note		None.
*
******************************************************************************/
static void IntrHandler(void *CallBackRef, u32 Bank, u32 Status)
{
	XGpioPs *Gpio = (XGpioPs *)CallBackRef;
	u32 DataRead;

	/* Push the switch button */
	DataRead = XGpioPs_ReadPin(Gpio, Input_Pin);
	if (DataRead != 0) {

		AllButtonsPressed = TRUE;
	}
}