实践内容：

1.使用定时器TA2捕获四个轮子编码器的信号

2.上升下降沿都捕获

3.串口定时反馈捕获值

程序编写：

程序设计方面十分简单，分为以下步骤,每个步骤有一些注意点：

一、初始化定时器：

            1.关闭定时溢出中断，开启捕获事件的中断

            2.选择合适的定时器频率，略高于编码器最大频率即可

        3.四个通道除了引脚不同，初始化基本一样，结构体名称改改就行

            4.设置为上升沿、下降沿、上升下降沿，三种捕获模式之一，（本文设置为上升下降都捕获    ）

二、捕获事件中断服务函数：

            1.因为之前关闭了定时溢出中断，所以void TA2_N_IRQHandler(void)的进入条件只有捕获事件到来时：（本文捕获事件为：上升下降都是捕获事件    ），就会进一次中断

             2.定时器配置捕获后，可以通过读取TAxIV寄存器来判断是哪个通道传来的捕获事件，借此对其计数。（本文是定时器2，因此读取TA2IV）

             3.

有关TAxIV寄存器介绍在801页

1.初始化定时器TA2四条通道的捕获：

注意点在之前说过了：

开启定时器计时，但关闭计时溢出中断

选择合适的计时溢出频率，这决定了捕获的采样率，比编码器脉冲频率快就行，当然，直接定时器48M也是没有问题的

四条通道初始化相同的

开启TA2端口中断 MAP_Interrupt_enableInterrupt(INT_TA2_N);

//定时器TA2捕获初始化:
void TA2_CAP_init(void)
{//四个通道初始化输入MAP_GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P5,GPIO_PIN6,GPIO_PRIMARY_MODULE_FUNCTION);	MAP_GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P5,GPIO_PIN7,GPIO_PRIMARY_MODULE_FUNCTION);	MAP_GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P6,GPIO_PIN6,GPIO_PRIMARY_MODULE_FUNCTION);	MAP_GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P6,GPIO_PIN7,GPIO_PRIMARY_MODULE_FUNCTION);	//定时器连续计数模式初始化，关闭定时溢出中断const Timer_A_ContinuousModeConfig continuousModeConfig ={TIMER_A_CLOCKSOURCE_SMCLK,TIMER_A_CLOCKSOURCE_DIVIDER_1,  //1分频，分辨率最高48MTIMER_A_TAIE_INTERRUPT_DISABLE, TIMER_A_SKIP_CLEAR};
//初始化通道1：const Timer_A_CaptureModeConfig captureModeConfig_1 ={TIMER_A_CAPTURECOMPARE_REGISTER_1, TIMER_A_CAPTUREMODE_RISING_AND_FALLING_EDGE,TIMER_A_CAPTURE_INPUTSELECT_CCIxA,TIMER_A_CAPTURE_SYNCHRONOUS,TIMER_A_CAPTURECOMPARE_INTERRUPT_ENABLE,TIMER_A_OUTPUTMODE_OUTBITVALUE};
//初始化通道2：const Timer_A_CaptureModeConfig captureModeConfig_2 ={TIMER_A_CAPTURECOMPARE_REGISTER_2, TIMER_A_CAPTUREMODE_RISING_AND_FALLING_EDGE,TIMER_A_CAPTURE_INPUTSELECT_CCIxA,TIMER_A_CAPTURE_SYNCHRONOUS,TIMER_A_CAPTURECOMPARE_INTERRUPT_ENABLE,TIMER_A_OUTPUTMODE_OUTBITVALUE};
//初始化通道3：const Timer_A_CaptureModeConfig captureModeConfig_3 ={TIMER_A_CAPTURECOMPARE_REGISTER_3, TIMER_A_CAPTUREMODE_RISING_AND_FALLING_EDGE,TIMER_A_CAPTURE_INPUTSELECT_CCIxA,TIMER_A_CAPTURE_SYNCHRONOUS,TIMER_A_CAPTURECOMPARE_INTERRUPT_ENABLE,TIMER_A_OUTPUTMODE_OUTBITVALUE};
//初始化通道4：const Timer_A_CaptureModeConfig captureModeConfig_4 ={TIMER_A_CAPTURECOMPARE_REGISTER_4, TIMER_A_CAPTUREMODE_RISING_AND_FALLING_EDGE,TIMER_A_CAPTURE_INPUTSELECT_CCIxA,TIMER_A_CAPTURE_SYNCHRONOUS,TIMER_A_CAPTURECOMPARE_INTERRUPT_ENABLE,TIMER_A_OUTPUTMODE_OUTBITVALUE};		MAP_Timer_A_initCapture(TIMER_A2_BASE, &captureModeConfig_1);MAP_Timer_A_initCapture(TIMER_A2_BASE, &captureModeConfig_2);MAP_Timer_A_initCapture(TIMER_A2_BASE, &captureModeConfig_3);MAP_Timer_A_initCapture(TIMER_A2_BASE, &captureModeConfig_4);MAP_Timer_A_configureContinuousMode(TIMER_A2_BASE, &continuousModeConfig);MAP_Interrupt_enableInterrupt(INT_TA2_N);MAP_Timer_A_startCounter(TIMER_A2_BASE, TIMER_A_CONTINUOUS_MODE);
}

2.编写定时器中断服务函数：

代码中的 Wheel[x].CAPTURE 无须在意，是我给每个轮子定义的结构体，换成普通变量一样用的，这种高速计数脉冲，需要大家时刻注意溢出问题，以下代码段的意思就是防止数据溢出不被记录：

if(Wheel[1].CAPTURE==62700){Wheel[1].CAPTURE=0;Wheel[1].CAT_OUT_TIME++;}


//这是捕获事件中断服务函数（因为定时器溢出中断已关闭）
//注意对照引脚看通道，这里通道情况与PWM控制不一样
void TA2_N_IRQHandler(void)
{uint16_t captureSource = TA2IV;
// 根据捕获通道来源进行适当的处理
//脉冲计数到62700时刚好车轮转95圈
//大电机减速比30编码器11线switch (captureSource) {case 0x02:// 处理TA2 CCR1通道的捕获中断Wheel[1].CAPTURE++;if(Wheel[1].CAPTURE==62700){Wheel[1].CAPTURE=0;Wheel[1].CAT_OUT_TIME++;}break;case 0x04:// 处理TA2 CCR2通道的捕获中断Wheel[2].CAPTURE++;if(Wheel[2].CAPTURE==62700){Wheel[2].CAPTURE=0;Wheel[2].CAT_OUT_TIME++;}		break;case 0x06:// 处理TA2 CCR3通道的捕获中断Wheel[3].CAPTURE++;if(Wheel[3].CAPTURE==62700){Wheel[3].CAPTURE=0;Wheel[3].CAT_OUT_TIME++;}					break;case 0x08:// 处理TA2 CCR4通道的捕获中断Wheel[4].CAPTURE++;if(Wheel[4].CAPTURE==62700){Wheel[4].CAPTURE=0;Wheel[4].CAT_OUT_TIME++;}					break;default: break;	
}
}

3.32定时器初始化为1s周期，通过串口反馈捕获情况：

//此句放在初始化，主函数开头，初始化32定时器为1s周期Tim32_0_Int_Init(47999999,1);//32定时器初始化函数，传入的aar psc决定了其周期
void Tim32_0_Int_Init(uint32_t aar, uint8_t psc)
{MAP_Timer32_initModule(TIMER32_0_BASE, psc, TIMER32_32BIT, TIMER32_PERIODIC_MODE);MAP_Timer32_setCount(TIMER32_0_BASE, aar);MAP_Timer32_enableInterrupt(TIMER32_0_BASE);MAP_Timer32_startTimer(TIMER32_0_BASE, false); //连续计数模式 falseMAP_Interrupt_enableInterrupt(INT_T32_INT1);
}/* Timer32 ISR 中断服务函数，1s进一次*/
void T32_INT1_IRQHandler(void)
{MAP_Timer32_clearInterruptFlag(TIMER32_0_BASE);printf("W1_CAP=%d\r\n",Wheel[1].CAPTURE);printf("W2_CAP=%d\r\n",Wheel[2].CAPTURE);printf("W3_CAP=%d\r\n",Wheel[3].CAPTURE);printf("W4_CAP=%d\r\n",Wheel[4].CAPTURE);
}

整体代码：

#include "main.h"//单个车轮状态与参数结构体：
Wheel_dat Wheel[5];int main(void)
{inint_all();   //初始化所有模块while (1){  }
}/* Timer32 ISR */
void T32_INT1_IRQHandler(void)
{MAP_Timer32_clearInterruptFlag(TIMER32_0_BASE);printf("W1_CAP=%d\r\n",Wheel[1].CAPTURE);printf("W2_CAP=%d\r\n",Wheel[2].CAPTURE);printf("W3_CAP=%d\r\n",Wheel[3].CAPTURE);printf("W4_CAP=%d\r\n",Wheel[4].CAPTURE);
}//初始化所有模块
void inint_all(void)
{SysInit();                                  //时钟配置    delay_init();								 								//delay_ms函数配置uart_init(115200);	TA2_CAP_init();Tim32_0_Int_Init(47999999,1);printf("Hello,MSP432!\r\n");								//串口打印测试字符MAP_Interrupt_enableMaster();               // 开启总中断
}//串口0服务函数
//串口0接收命令，存在数组中
void EUSCIA0_IRQHandler(void)
{uint32_t status = UART_getEnabledInterruptStatus(EUSCI_A0_BASE);if(status & EUSCI_A_UART_RECEIVE_INTERRUPT_FLAG)      //接收中断{USART0_save[USART0_xb++]=MAP_UART_receiveData(EUSCI_A0_BASE);if(USART0_xb== 20){USART0_xb=0;	}							      //下标最大不超过20if(USART0_save[USART0_xb-1]=='\0'){USART0_flag=1;}  //命令以\0结尾}
}//这是捕获事件中断服务函数（因为定时器溢出中断已关闭）
//注意对照引脚看通道，这里通道情况与PWM控制不一样
void TA2_N_IRQHandler(void)
{uint16_t captureSource = TA2IV;
// 根据捕获通道来源进行适当的处理
//脉冲计数到62700时刚好车轮转95圈
//大电机减速比30编码器11线switch (captureSource) {case 0x02:// 处理TA2 CCR1通道的捕获中断Wheel[1].CAPTURE++;if(Wheel[1].CAPTURE==62700){Wheel[1].CAPTURE=0;Wheel[1].CAT_OUT_TIME++;}break;case 0x04:// 处理TA2 CCR2通道的捕获中断Wheel[2].CAPTURE++;if(Wheel[2].CAPTURE==62700){Wheel[2].CAPTURE=0;Wheel[2].CAT_OUT_TIME++;}		break;case 0x06:// 处理TA2 CCR3通道的捕获中断Wheel[3].CAPTURE++;if(Wheel[3].CAPTURE==62700){Wheel[3].CAPTURE=0;Wheel[3].CAT_OUT_TIME++;}					break;case 0x08:// 处理TA2 CCR4通道的捕获中断Wheel[4].CAPTURE++;if(Wheel[4].CAPTURE==62700){Wheel[4].CAPTURE=0;Wheel[4].CAT_OUT_TIME++;}					break;default: break;	
}
}			//定时器TA2捕获初始化:
void TA2_CAP_init(void)
{//四个通道初始化输入MAP_GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P5,GPIO_PIN6,GPIO_PRIMARY_MODULE_FUNCTION);	MAP_GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P5,GPIO_PIN7,GPIO_PRIMARY_MODULE_FUNCTION);	MAP_GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P6,GPIO_PIN6,GPIO_PRIMARY_MODULE_FUNCTION);	MAP_GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P6,GPIO_PIN7,GPIO_PRIMARY_MODULE_FUNCTION);	//定时器连续计数模式初始化，关闭定时溢出中断const Timer_A_ContinuousModeConfig continuousModeConfig ={TIMER_A_CLOCKSOURCE_SMCLK,TIMER_A_CLOCKSOURCE_DIVIDER_1,  //1分频，分辨率最高48MTIMER_A_TAIE_INTERRUPT_DISABLE, TIMER_A_SKIP_CLEAR};
//初始化通道1：const Timer_A_CaptureModeConfig captureModeConfig_1 ={TIMER_A_CAPTURECOMPARE_REGISTER_1, TIMER_A_CAPTUREMODE_RISING_AND_FALLING_EDGE,TIMER_A_CAPTURE_INPUTSELECT_CCIxA,TIMER_A_CAPTURE_SYNCHRONOUS,TIMER_A_CAPTURECOMPARE_INTERRUPT_ENABLE,TIMER_A_OUTPUTMODE_OUTBITVALUE};
//初始化通道2：const Timer_A_CaptureModeConfig captureModeConfig_2 ={TIMER_A_CAPTURECOMPARE_REGISTER_2, TIMER_A_CAPTUREMODE_RISING_AND_FALLING_EDGE,TIMER_A_CAPTURE_INPUTSELECT_CCIxA,TIMER_A_CAPTURE_SYNCHRONOUS,TIMER_A_CAPTURECOMPARE_INTERRUPT_ENABLE,TIMER_A_OUTPUTMODE_OUTBITVALUE};
//初始化通道3：const Timer_A_CaptureModeConfig captureModeConfig_3 ={TIMER_A_CAPTURECOMPARE_REGISTER_3, TIMER_A_CAPTUREMODE_RISING_AND_FALLING_EDGE,TIMER_A_CAPTURE_INPUTSELECT_CCIxA,TIMER_A_CAPTURE_SYNCHRONOUS,TIMER_A_CAPTURECOMPARE_INTERRUPT_ENABLE,TIMER_A_OUTPUTMODE_OUTBITVALUE};
//初始化通道4：const Timer_A_CaptureModeConfig captureModeConfig_4 ={TIMER_A_CAPTURECOMPARE_REGISTER_4, TIMER_A_CAPTUREMODE_RISING_AND_FALLING_EDGE,TIMER_A_CAPTURE_INPUTSELECT_CCIxA,TIMER_A_CAPTURE_SYNCHRONOUS,TIMER_A_CAPTURECOMPARE_INTERRUPT_ENABLE,TIMER_A_OUTPUTMODE_OUTBITVALUE};		MAP_Timer_A_initCapture(TIMER_A2_BASE, &captureModeConfig_1);MAP_Timer_A_initCapture(TIMER_A2_BASE, &captureModeConfig_2);MAP_Timer_A_initCapture(TIMER_A2_BASE, &captureModeConfig_3);MAP_Timer_A_initCapture(TIMER_A2_BASE, &captureModeConfig_4);MAP_Timer_A_configureContinuousMode(TIMER_A2_BASE, &continuousModeConfig);MAP_Interrupt_enableInterrupt(INT_TA2_N);MAP_Timer_A_startCounter(TIMER_A2_BASE, TIMER_A_CONTINUOUS_MODE);
}

#ifndef _main_h_
#define _main_h_#include <ti/devices/msp432p4xx/driverlib/driverlib.h>
#include "string.h"				   	//C标准库、字符串处理库
#include "sysinit.h"			   	//时钟配置
#include "delay.h"				   	//滴答定时器初始化(提供delay_ms延时)
#include "Public.h"
#include "DATA.h"//单个车轮状态与参数结构体：
typedef struct wheel_data
{uint16_t Sta;            //正反转状态，0不转，2正，1反uint16_t PWM_DIV;        //车轮电机占空比6 - 99uint32_t CAT_OUT_TIME;   //编码器 脉冲溢出次数，溢出一次就加一，记录有几个65530uint32_t CAPTURE;        //编码器 外部中断次数记录最大65530次脉冲，溢出后CAT_OUT_TIME会加一，CAPTURE归零uint32_t CAPTURE_LAST;   //上一次外部中断次数记录uint32_t CAPTURE_NEW;    //最新外部中断次数记录uint32_t DISTANCE;       //单轮行驶总路程长度单位cm,最大65535cmuint32_t SPEED;          //瞬时速度值存储,单位cm/s
}Wheel_dat;void inint_all(void);               //初始化所有模块
//定时器TA2捕获初始化:
void TA2_CAP_init(void);#endif