實踐內容：

1.使用定時器TA2捕獲四個輪子編碼器的信號

2.上升下降沿都捕獲

3.串口定時反饋捕獲值

程序編寫：

程序設計方面十分簡單，分為以下步驟,每個步驟有一些注意點：

一、初始化定時器：

??????????? 1.關閉定時溢出中斷，開啟捕獲事件的中斷

??????????? 2.選擇合適的定時器頻率，略高于編碼器最大頻率即可

??????? ? ? 3.四個通道除了引腳不同，初始化基本一樣，結構體名稱改改就行

??????????? 4.設置為上升沿、下降沿、上升下降沿，三種捕獲模式之一，（本文設置為上升下降都捕獲 ?? ）

二、捕獲事件中斷服務函數：

??????????? 1.因為之前關閉了定時溢出中斷，所以void TA2_N_IRQHandler(void)的進入條件只有捕獲事件到來時：（本文捕獲事件為：上升下降都是捕獲事件 ?? ），就會進一次中斷

???????????? 2.定時器配置捕獲后，可以通過讀取TAxIV寄存器來判斷是哪個通道傳來的捕獲事件，借此對其計數。（本文是定時器2，因此讀取TA2IV）

???????????? 3. ?? ?

?有關TAxIV寄存器介紹在801頁

?1.初始化定時器TA2四條通道的捕獲：

注意點在之前說過了：

開啟定時器計時，但關閉計時溢出中斷

選擇合適的計時溢出頻率，這決定了捕獲的采樣率，比編碼器脈沖頻率快就行，當然，直接定時器48M也是沒有問題的

四條通道初始化相同的

開啟TA2端口中斷 ??? MAP_Interrupt_enableInterrupt(INT_TA2_N);

//定時器TA2捕獲初始化:
void TA2_CAP_init(void)
{//四個通道初始化輸入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);	//定時器連續計數模式初始化，關閉定時溢出中斷const Timer_A_ContinuousModeConfig continuousModeConfig ={TIMER_A_CLOCKSOURCE_SMCLK,TIMER_A_CLOCKSOURCE_DIVIDER_1,  //1分頻，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.編寫定時器中斷服務函數：

代碼中的 Wheel[x].CAPTURE 無須在意，是我給每個輪子定義的結構體，換成普通變量一樣用的，這種高速計數脈沖，需要大家時刻注意溢出問題，以下代碼段的意思就是防止數據溢出不被記錄：

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


//這是捕獲事件中斷服務函數（因為定時器溢出中斷已關閉）
//注意對照引腳看通道，這里通道情況與PWM控制不一樣
void TA2_N_IRQHandler(void)
{uint16_t captureSource = TA2IV;
// 根據捕獲通道來源進行適當的處理
//脈沖計數到62700時剛好車輪轉95圈
//大電機減速比30編碼器11線switch (captureSource) {case 0x02:// 處理TA2 CCR1通道的捕獲中斷Wheel[1].CAPTURE++;if(Wheel[1].CAPTURE==62700){Wheel[1].CAPTURE=0;Wheel[1].CAT_OUT_TIME++;}break;case 0x04:// 處理TA2 CCR2通道的捕獲中斷Wheel[2].CAPTURE++;if(Wheel[2].CAPTURE==62700){Wheel[2].CAPTURE=0;Wheel[2].CAT_OUT_TIME++;}		break;case 0x06:// 處理TA2 CCR3通道的捕獲中斷Wheel[3].CAPTURE++;if(Wheel[3].CAPTURE==62700){Wheel[3].CAPTURE=0;Wheel[3].CAT_OUT_TIME++;}					break;case 0x08:// 處理TA2 CCR4通道的捕獲中斷Wheel[4].CAPTURE++;if(Wheel[4].CAPTURE==62700){Wheel[4].CAPTURE=0;Wheel[4].CAT_OUT_TIME++;}					break;default: break;	
}
}

3.32定時器初始化為1s周期，通過串口反饋捕獲情況：

//此句放在初始化，主函數開頭，初始化32定時器為1s周期Tim32_0_Int_Init(47999999,1);//32定時器初始化函數，傳入的aar psc決定了其周期
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); //連續計數模式 falseMAP_Interrupt_enableInterrupt(INT_T32_INT1);
}/* Timer32 ISR 中斷服務函數，1s進一次*/
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);
}

整體代碼：

#include "main.h"//單個車輪狀態與參數結構體：
Wheel_dat Wheel[5];int main(void)
{inint_all();   //初始化所有模塊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);
}//初始化所有模塊
void inint_all(void)
{SysInit();                                  //時鐘配置    delay_init();								 								//delay_ms函數配置uart_init(115200);	TA2_CAP_init();Tim32_0_Int_Init(47999999,1);printf("Hello,MSP432!\r\n");								//串口打印測試字符MAP_Interrupt_enableMaster();               // 開啟總中斷
}//串口0服務函數
//串口0接收命令，存在數組中
void EUSCIA0_IRQHandler(void)
{uint32_t status = UART_getEnabledInterruptStatus(EUSCI_A0_BASE);if(status & EUSCI_A_UART_RECEIVE_INTERRUPT_FLAG)      //接收中斷{USART0_save[USART0_xb++]=MAP_UART_receiveData(EUSCI_A0_BASE);if(USART0_xb== 20){USART0_xb=0;	}							      //下標最大不超過20if(USART0_save[USART0_xb-1]=='\0'){USART0_flag=1;}  //命令以\0結尾}
}//這是捕獲事件中斷服務函數（因為定時器溢出中斷已關閉）
//注意對照引腳看通道，這里通道情況與PWM控制不一樣
void TA2_N_IRQHandler(void)
{uint16_t captureSource = TA2IV;
// 根據捕獲通道來源進行適當的處理
//脈沖計數到62700時剛好車輪轉95圈
//大電機減速比30編碼器11線switch (captureSource) {case 0x02:// 處理TA2 CCR1通道的捕獲中斷Wheel[1].CAPTURE++;if(Wheel[1].CAPTURE==62700){Wheel[1].CAPTURE=0;Wheel[1].CAT_OUT_TIME++;}break;case 0x04:// 處理TA2 CCR2通道的捕獲中斷Wheel[2].CAPTURE++;if(Wheel[2].CAPTURE==62700){Wheel[2].CAPTURE=0;Wheel[2].CAT_OUT_TIME++;}		break;case 0x06:// 處理TA2 CCR3通道的捕獲中斷Wheel[3].CAPTURE++;if(Wheel[3].CAPTURE==62700){Wheel[3].CAPTURE=0;Wheel[3].CAT_OUT_TIME++;}					break;case 0x08:// 處理TA2 CCR4通道的捕獲中斷Wheel[4].CAPTURE++;if(Wheel[4].CAPTURE==62700){Wheel[4].CAPTURE=0;Wheel[4].CAT_OUT_TIME++;}					break;default: break;	
}
}			//定時器TA2捕獲初始化:
void TA2_CAP_init(void)
{//四個通道初始化輸入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);	//定時器連續計數模式初始化，關閉定時溢出中斷const Timer_A_ContinuousModeConfig continuousModeConfig ={TIMER_A_CLOCKSOURCE_SMCLK,TIMER_A_CLOCKSOURCE_DIVIDER_1,  //1分頻，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標準庫、字符串處理庫
#include "sysinit.h"			   	//時鐘配置
#include "delay.h"				   	//滴答定時器初始化(提供delay_ms延時)
#include "Public.h"
#include "DATA.h"//單個車輪狀態與參數結構體：
typedef struct wheel_data
{uint16_t Sta;            //正反轉狀態，0不轉，2正，1反uint16_t PWM_DIV;        //車輪電機占空比6 - 99uint32_t CAT_OUT_TIME;   //編碼器 脈沖溢出次數，溢出一次就加一，記錄有幾個65530uint32_t CAPTURE;        //編碼器 外部中斷次數記錄最大65530次脈沖，溢出后CAT_OUT_TIME會加一，CAPTURE歸零uint32_t CAPTURE_LAST;   //上一次外部中斷次數記錄uint32_t CAPTURE_NEW;    //最新外部中斷次數記錄uint32_t DISTANCE;       //單輪行駛總路程長度單位cm,最大65535cmuint32_t SPEED;          //瞬時速度值存儲,單位cm/s
}Wheel_dat;void inint_all(void);               //初始化所有模塊
//定時器TA2捕獲初始化:
void TA2_CAP_init(void);#endif