ZYNQ 学习之UART中断库函数解读

通用异步收发传输器（Universal Asynchronous Receiver/Transmitter)，通常称作UART。

百度百科原理介绍：https://baike.baidu.com/item/UART/4429746?fr=aladdin

1.初始化函数：XUartPs_CfgInitialize(UartInstPtr, Config, Config->BaseAddress);

首先是对结构变量的初始化，基地址，ID ,频率，波特率的设置

XUartPs_SetBaudRate(InstancePtr, BaudRate);   //欧特吕设置函数

接下来设置数据模式寄存器来设置工作模式：数据位数、有无停止位，有无奇偶校验、时钟有无分频等。

        ModeRegister = XUartPs_ReadReg(InstancePtr->Config.BaseAddress,
                      XUARTPS_MR_OFFSET);

//

        /* Mask off what's already there */
        ModeRegister &= (~((u32)XUARTPS_MR_CHARLEN_MASK |
                         (u32)XUARTPS_MR_STOPMODE_MASK |
                         (u32)XUARTPS_MR_PARITY_MASK));

//

        /* Set the register value to the desired data format */
        ModeRegister |=    ((u32)XUARTPS_MR_CHARLEN_8_BIT |
                         (u32)XUARTPS_MR_STOPMODE_1_BIT |
                         (u32)XUARTPS_MR_PARITY_NONE);

//

        /* Write the mode register out */
        XUartPs_WriteReg(InstancePtr->Config.BaseAddress, XUARTPS_MR_OFFSET,
                   ModeRegister);

        /* Set the RX FIFO trigger at 8 data bytes. */
        XUartPs_WriteReg(InstancePtr->Config.BaseAddress,
                   XUARTPS_RXWM_OFFSET, 0x08U)；       //设置接收8bit触发

        /* Set the RX timeout to 1, which will be 4 character time */
        XUartPs_WriteReg(InstancePtr->Config.BaseAddress,
                   XUARTPS_RXTOUT_OFFSET, 0x01U)；

//设置接收超时，意思就是经过多少个周期后，没有接收数据，就停止接收，4*设置的值 个周期

        /* Disable all interrupts, polled mode is the default */
        XUartPs_WriteReg(InstancePtr->Config.BaseAddress, XUARTPS_IDR_OFFSET,
                   XUARTPS_IXR_MASK);
 

2.XUartPs_SetHandler(UartInstPtr, (XUartPs_Handler)UartPs_Intr_Handler, UartInstPtr);

//设置中断触发时的回调函数,即中断触发处理函数

 

 3.XUartPs_SetInterruptMask(XUartPs *InstancePtr, u32 Mask)

//设置中断使能触发器，主要涉及两个寄存器的写

    /* Write the mask to the IER Register */
    XUartPs_WriteReg(InstancePtr->Config.BaseAddress,
         XUARTPS_IER_OFFSET, TempMask);

    /* Write the inverse of the Mask to the IDR register */
    XUartPs_WriteReg(InstancePtr->Config.BaseAddress,
         XUARTPS_IDR_OFFSET, (~TempMask));

4. XUartPs_SetRecvTimeout(XUartPs *InstancePtr, u8 RecvTimeout)

* This function sets the Receive Timeout of the UART.
*
* @param    InstancePtr is a pointer to the XUartPs instance.
* @param    RecvTimeout setting allows the UART to detect an idle connection
*        on the reciever data line.
*        Timeout duration = RecvTimeout x 4 x Bit Period. 0 disables the
*        timeout function.

5.UartPs_Intr_Handler(void *CallBackRef, u32 Event, unsigned int EventData)

//中断触发处理函数，首先判断是哪一种中断产生，不同触发方式，采取不同的处理方法

（1）/* All of the data has been sent */

（2）/* All of the data has been received */

（3）    /*
     * Data was received, but not the expected number of bytes, a
     * timeout just indicates the data stopped for 8 character times
     */

（4）    /*
     * Data was received with an error, keep the data but determine
     * what kind of errors occurred
     */

（5）/*
     * Data was received with an parity or frame or break error, keep the data
     * but determine what kind of errors occurred. Specific to Zynq Ultrascale+
     * MP.
     */

（6）/*
     * Data was received with an overrun error, keep the data but determine
     * what kind of errors occurred. Specific to Zynq Ultrascale+ MP.
     */

中断函数必要的几个函数：

#define INTC_DEVICE_ID          XPAR_SCUGIC_SINGLE_DEVICE_ID

XScuGic Intc; //GIC

void Setup_Intr_Exception(XScuGic * IntcInstancePtr)
{
	/* Enable interrupts from the hardware */
	Xil_ExceptionInit();
	Xil_ExceptionRegisterHandler(XIL_EXCEPTION_ID_INT,
			(Xil_ExceptionHandler)XScuGic_InterruptHandler,
			(void *)IntcInstancePtr);

	Xil_ExceptionEnable();
}

int Init_Intr_System(XScuGic * IntcInstancePtr)
{
	int Status;

	XScuGic_Config *IntcConfig;
	/*
	 * 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(IntcInstancePtr, IntcConfig,
					IntcConfig->CpuBaseAddress);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}
	return XST_SUCCESS;
}

外设中断函数的写法：

1.外设初始化，查找ID，基地址，进行必要的外设参数的初始化。

2.外设中断的初始化：查找中断外设的ID，初始化，三个Xil_Exception函数的编写，允许ARM处理器中断；

3.中断函数的连接，中断ID号，使能中断。

头文件：

/*
 * uartps_intr.h
 *
 *  Created on: 2019年5月3日
 *      Author: Administrator
 */

#ifndef SRC_UARTPS_INTR_H_
#define SRC_UARTPS_INTR_H_

#include "xparameters.h"
#include "xplatform_info.h"
#include "xuartps.h"
#include "xil_exception.h"
#include "xil_printf.h"
#include "xscugic.h"

#define INTC_DEVICE_ID          XPAR_SCUGIC_SINGLE_DEVICE_ID
#define UART_DEVICE_ID		XPAR_XUARTPS_0_DEVICE_ID
#define INTC_DEVICE_ID		XPAR_SCUGIC_SINGLE_DEVICE_ID
#define UART_INT_IRQ_ID		XPAR_XUARTPS_1_INTR

#define TEST_BUFFER_SIZE	10

XUartPs UartPs;//uart
XScuGic Intc; //GIC

static u8 SendBuffer[TEST_BUFFER_SIZE];	/* Buffer for Transmitting Data */
static u8 RecvBuffer[TEST_BUFFER_SIZE];	/* Buffer for Receiving Data */

volatile int TotalReceivedCount;
volatile int TotalSentCount;
int TotalErrorCount;

int Init_UartPsIntr(XUartPs *UartInstPtr,u16 DeviceId);

int UartPs_Setup_IntrSystem(XScuGic *IntcInstancePtr,XUartPs *UartInstancePtr,u16 UartIntrId);

void UartPs_Intr_Handler(void *CallBackRef, u32 Event, unsigned int EventData);

#endif /* SRC_UARTPS_INTR_H_ */



子函数文件：
/*
 * uartps_intr.c
 *
 * Created on: 2019年05月02日
 * www.osrc.cn
 * copyright by cz123 msxbo
*/
#include "uartps_intr.h"


int Init_UartPsIntr(XUartPs *UartInstPtr,u16 DeviceId )
{
	int Status;
	XUartPs_Config *Config;
	u32 IntrMask;

	if (XGetPlatform_Info() == XPLAT_ZYNQ_ULTRA_MP) {
#ifdef XPAR_XUARTPS_1_DEVICE_ID
		DeviceId = XPAR_XUARTPS_1_DEVICE_ID;
#endif
	}

	Config = XUartPs_LookupConfig(DeviceId);//基地址0xE0001000，时钟100 000 000
	if (NULL == Config) {
		return XST_FAILURE;
	}

	Status = XUartPs_CfgInitialize(UartInstPtr, Config, Config->BaseAddress);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}


	/*
	 * Setup the handlers for the UART that will be called from the
	 * interrupt context when data has been sent and received, specify
	 * a pointer to the UART driver instance as the callback reference
	 * so the handlers are able to access the instance data
	 */
	XUartPs_SetHandler(UartInstPtr, (XUartPs_Handler)UartPs_Intr_Handler, UartInstPtr);

	/*
	 * Enable the interrupt of the UART so interrupts will occur, setup
	 * a local loopback so data that is sent will be received.
	 */
	IntrMask =
		XUARTPS_IXR_TOUT | XUARTPS_IXR_PARITY | XUARTPS_IXR_FRAMING |
		XUARTPS_IXR_OVER | XUARTPS_IXR_TXEMPTY | XUARTPS_IXR_RXFULL |
		XUARTPS_IXR_RXOVR;

	if (UartInstPtr->Platform == XPLAT_ZYNQ_ULTRA_MP) {
		IntrMask |= XUARTPS_IXR_RBRK;
	}

	XUartPs_SetInterruptMask(UartInstPtr, IntrMask);

	XUartPs_SetRecvTimeout(UartInstPtr, 8);

	return XST_SUCCESS;
}


void UartPs_Intr_Handler(void *CallBackRef, u32 Event, unsigned int EventData)
{
	int i = 0;
	/* All of the data has been sent */
	if (Event == XUARTPS_EVENT_SENT_DATA) {
		TotalSentCount = EventData;
	}

	/* All of the data has been received */
	if (Event == XUARTPS_EVENT_RECV_DATA) {
		TotalReceivedCount = EventData;
		if(TotalReceivedCount == TEST_BUFFER_SIZE) {
			for(i=0;iCpuBaseAddress);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}

	/* Enable interrupts from the hardware */
		Xil_ExceptionInit();
		Xil_ExceptionRegisterHandler(XIL_EXCEPTION_ID_INT,
				(Xil_ExceptionHandler)XScuGic_InterruptHandler,
				(void *)IntcInstancePtr);

		Xil_ExceptionEnable();



	/*
	 * interrupt for the device occurs, the device driver handler
	 * performs the specific interrupt processing for the device
	 */
	Status = XScuGic_Connect(IntcInstancePtr, UartIntrId,
				  (Xil_ExceptionHandler) XUartPs_InterruptHandler,
				  (void *) UartInstancePtr);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}

	/* Enable the interrupt for the device */
	XScuGic_Enable(IntcInstancePtr, UartIntrId);

	return XST_SUCCESS;
}




测试主程序：

#include "uartps_intr.h"


int main(void)
{

	Init_UartPsIntr(&UartPs,UART_DEVICE_ID);
	UartPs_Setup_IntrSystem(&Intc, &UartPs, UART_INT_IRQ_ID);
	//测试函数
	XUartPs_Recv(&UartPs, RecvBuffer, TEST_BUFFER_SIZE);
    while(1);
	return 0;
}