目錄

• 1.通過Timer_A_outputPWM配置產生PWM波
• • 初始化函數
  • 計算
  • 修改占空比的函數
  • 整體程序
  • 效果
• 2.單定時器產生多路PWM信號
• • 初始化函數
  • 實驗結果
• 3.對稱PWM信號的產生
• • 初始化程序
  • 實驗結果

平臺：Code Composer Studio 10.3.1
MSP430F5529 LaunchPad? Development Kit
(MSP?EXP430F5529LP)

---

???????

1.通過Timer_A_outputPWM配置產生PWM波

所選輸出引腳為P1.2

初始化函數

#define TIMER_PERIOD 12500 void Timer_A_PWM_Init(void) {Timer_A_outputPWMParam htim = {0};//P1.2復用輸出GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P1, GPIO_PIN2); //時鐘源選為SMCLK = 25MHzhtim.clockSource = TIMER_A_CLOCKSOURCE_SMCLK; //分頻系數設為40htim.clockSourceDivider = TIMER_A_CLOCKSOURCE_DIVIDER_40;//裝載值設為12500 - 1htim.timerPeriod = TIMER_PERIOD - 1;//P1.2 對應 TA0.1 故設為TIMER_A_CAPTURECOMPARE_REGISTER_1htim.compareRegister = TIMER_A_CAPTURECOMPARE_REGISTER_1;htim.compareOutputMode = TIMER_A_OUTPUTMODE_RESET_SET;//初始比較值為裝載值的一半 即初始占空比為50%htim.dutyCycle = TIMER_PERIOD / 2;//P1.2 對應 TA0.1 為TIMER_A0_BASETimer_A_outputPWM(TIMER_A0_BASE, &htim); }

計算

時鐘源為SMCLK = 25MHz
分頻系數為40
裝載值為12500 - 1
故所得PWM頻率為25MHz/40/12500=50Hz

修改占空比的函數

修改占空比即修改比較值，故使用Timer_A_setCompareValue函數

我選擇在外部中斷服務函數內進行修改，按下一次按鈕分別為占空比減少10%和增加10%

//****************************************************************************** // //This is the PORT2_VECTOR interrupt vector service routine // //****************************************************************************** #pragma vector=PORT2_VECTOR // P2口中斷源 __interrupt void Port_2 (void) // 聲明一個中斷服務程序，名為Port_2() {if(GPIO_getInterruptStatus(GPIO_PORT_P2, GPIO_PIN1)){delay_ms(20);if(!GPIO_getInputPinValue(GPIO_PORT_P2, GPIO_PIN1)){//P1.0 = toggleTimer_A_setCompareValue(TIMER_A0_BASE,TIMER_A_CAPTURECOMPARE_REGISTER_1,Timer_A_getCaptureCompareCount(TIMER_A0_BASE, TIMER_A_CAPTURECOMPARE_REGISTER_1) - TIMER_PERIOD / 10);while(!GPIO_getInputPinValue(GPIO_PORT_P2, GPIO_PIN1));}//P2.1 IFG clearedGPIO_clearInterrupt(GPIO_PORT_P2, GPIO_PIN1);} }//****************************************************************************** // //This is the PORT1_VECTOR interrupt vector service routine // //****************************************************************************** #pragma vector=PORT1_VECTOR // P2口中斷源 __interrupt void Port_1 (void) // 聲明一個中斷服務程序，名為Port_1() {if(GPIO_getInterruptStatus(GPIO_PORT_P1, GPIO_PIN1)){delay_ms(20);if(!GPIO_getInputPinValue(GPIO_PORT_P1, GPIO_PIN1)){//P1.0 = toggleTimer_A_setCompareValue(TIMER_A0_BASE,TIMER_A_CAPTURECOMPARE_REGISTER_1,Timer_A_getCaptureCompareCount(TIMER_A0_BASE, TIMER_A_CAPTURECOMPARE_REGISTER_1) + TIMER_PERIOD / 10);while(!GPIO_getInputPinValue(GPIO_PORT_P1, GPIO_PIN1));}//P2.1 IFG clearedGPIO_clearInterrupt(GPIO_PORT_P1, GPIO_PIN1);} }

整體程序

#include "driverlib.h"#define MCLK_IN_HZ 25000000#define delay_us(x) __delay_cycles((MCLK_IN_HZ/1000000*(x))) #define delay_ms(x) __delay_cycles((MCLK_IN_HZ/1000*(x)))void SystemClock_Init(void) {PMM_setVCore(PMM_CORE_LEVEL_3); //高主頻工作需要較高的核心電壓//XT1引腳復用GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P5, GPIO_PIN4);GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P5, GPIO_PIN5);//起振XT1UCS_turnOnLFXT1(UCS_XT1_DRIVE_3,UCS_XCAP_3);//XT2引腳復用GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P5, GPIO_PIN2);GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P5, GPIO_PIN3);//起振XT2UCS_turnOnXT2(UCS_XT2_DRIVE_4MHZ_8MHZ);//XT2作為FLL參考時鐘，先8分頻，再50倍頻 4MHz / 8 * 50 = 25MHzUCS_initClockSignal(UCS_FLLREF, UCS_XT2CLK_SELECT, UCS_CLOCK_DIVIDER_8);UCS_initFLLSettle(25000, 50);//XT1作為ACLK時鐘源 = 32768HzUCS_initClockSignal(UCS_ACLK, UCS_XT1CLK_SELECT, UCS_CLOCK_DIVIDER_1);//DCOCLK作為MCLK時鐘源 = 25MHzUCS_initClockSignal(UCS_MCLK, UCS_DCOCLK_SELECT, UCS_CLOCK_DIVIDER_1);//DCOCLK作為SMCLK時鐘源 = 25MHzUCS_initClockSignal(UCS_SMCLK, UCS_DCOCLK_SELECT, UCS_CLOCK_DIVIDER_1);//設置外部時鐘源的頻率，使得在調用UCS_getMCLK, UCS_getSMCLK 或 UCS_getACLK時可得到正確值UCS_setExternalClockSource(32768, 4000000); }#define TIMER_PERIOD 12500 void Timer_A_PWM_Init(void) {Timer_A_outputPWMParam htim = {0};GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P1, GPIO_PIN2);htim.clockSource = TIMER_A_CLOCKSOURCE_SMCLK;htim.clockSourceDivider = TIMER_A_CLOCKSOURCE_DIVIDER_40;htim.timerPeriod = TIMER_PERIOD - 1;htim.compareRegister = TIMER_A_CAPTURECOMPARE_REGISTER_1;htim.compareOutputMode = TIMER_A_OUTPUTMODE_RESET_SET;htim.dutyCycle = TIMER_PERIOD / 2;Timer_A_outputPWM(TIMER_A0_BASE, &htim); }void KEY_S1_Init(void) {GPIO_setAsInputPinWithPullUpResistor(GPIO_PORT_P2, GPIO_PIN1);//P2.1 interrupt enabledGPIO_enableInterrupt(GPIO_PORT_P2, GPIO_PIN1); //使能中斷//P2.1 Hi/Lo edgeGPIO_selectInterruptEdge(GPIO_PORT_P2, GPIO_PIN1, GPIO_HIGH_TO_LOW_TRANSITION); //設置中斷類型//P2.1 IFG clearedGPIO_clearInterrupt(GPIO_PORT_P2, GPIO_PIN1); //清除中斷標志位 }void KEY_S2_Init(void) {GPIO_setAsInputPinWithPullUpResistor(GPIO_PORT_P1, GPIO_PIN1);//P2.1 interrupt enabledGPIO_enableInterrupt(GPIO_PORT_P1, GPIO_PIN1); //使能中斷//P2.1 Hi/Lo edgeGPIO_selectInterruptEdge(GPIO_PORT_P1, GPIO_PIN1, GPIO_HIGH_TO_LOW_TRANSITION); //設置中斷類型//P2.1 IFG clearedGPIO_clearInterrupt(GPIO_PORT_P1, GPIO_PIN1); //清除中斷標志位 }int main(void) {WDT_A_hold(WDT_A_BASE);SystemClock_Init();Timer_A_PWM_Init();KEY_S1_Init();KEY_S2_Init();//interrupts enabled__bis_SR_register(GIE);while(1){} }//****************************************************************************** // //This is the PORT2_VECTOR interrupt vector service routine // //****************************************************************************** #pragma vector=PORT2_VECTOR // P2口中斷源 __interrupt void Port_2 (void) // 聲明一個中斷服務程序，名為Port_2() {if(GPIO_getInterruptStatus(GPIO_PORT_P2, GPIO_PIN1)){delay_ms(20);if(!GPIO_getInputPinValue(GPIO_PORT_P2, GPIO_PIN1)){//P1.0 = toggleTimer_A_setCompareValue(TIMER_A0_BASE,TIMER_A_CAPTURECOMPARE_REGISTER_1,Timer_A_getCaptureCompareCount(TIMER_A0_BASE, TIMER_A_CAPTURECOMPARE_REGISTER_1) - TIMER_PERIOD / 10);while(!GPIO_getInputPinValue(GPIO_PORT_P2, GPIO_PIN1));}//P2.1 IFG clearedGPIO_clearInterrupt(GPIO_PORT_P2, GPIO_PIN1);} }//****************************************************************************** // //This is the PORT1_VECTOR interrupt vector service routine // //****************************************************************************** #pragma vector=PORT1_VECTOR // P2口中斷源 __interrupt void Port_1 (void) // 聲明一個中斷服務程序，名為Port_1() {if(GPIO_getInterruptStatus(GPIO_PORT_P1, GPIO_PIN1)){delay_ms(20);if(!GPIO_getInputPinValue(GPIO_PORT_P1, GPIO_PIN1)){//P1.0 = toggleTimer_A_setCompareValue(TIMER_A0_BASE,TIMER_A_CAPTURECOMPARE_REGISTER_1,Timer_A_getCaptureCompareCount(TIMER_A0_BASE, TIMER_A_CAPTURECOMPARE_REGISTER_1) + TIMER_PERIOD / 10);while(!GPIO_getInputPinValue(GPIO_PORT_P1, GPIO_PIN1));}//P2.1 IFG clearedGPIO_clearInterrupt(GPIO_PORT_P1, GPIO_PIN1);} }

效果

2.單定時器產生多路PWM信號

初始化函數

#define TIMER_PERIOD 12500 void Timer_A_PWM_Init(void) { //復用P1.2、P1.3、P1.4、P1.5輸出GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P1, GPIO_PIN2|GPIO_PIN3|GPIO_PIN4|GPIO_PIN5);Timer_A_initUpModeParam htim = {0};htim.clockSource = TIMER_A_CLOCKSOURCE_SMCLK;htim.clockSourceDivider = TIMER_A_CLOCKSOURCE_DIVIDER_40;htim.timerPeriod = TIMER_PERIOD - 1;htim.timerInterruptEnable_TAIE = TIMER_A_TAIE_INTERRUPT_DISABLE;htim.captureCompareInterruptEnable_CCR0_CCIE = TIMER_A_CCIE_CCR0_INTERRUPT_DISABLE;htim.timerClear = TIMER_A_DO_CLEAR;htim.startTimer = true;Timer_A_initUpMode(TIMER_A0_BASE, &htim);Timer_A_initCompareModeParam htim_PWM = {0};htim_PWM.compareInterruptEnable = TIMER_A_CAPTURECOMPARE_INTERRUPT_DISABLE;htim_PWM.compareOutputMode = TIMER_A_OUTPUTMODE_RESET_SET;htim_PWM.compareRegister = TIMER_A_CAPTURECOMPARE_REGISTER_1;htim_PWM.compareValue = (int)(TIMER_PERIOD * 0.2);//Initialize compare mode to generate PWM1Timer_A_initCompareMode(TIMER_A0_BASE, &htim_PWM);htim_PWM.compareRegister = TIMER_A_CAPTURECOMPARE_REGISTER_2;htim_PWM.compareValue = (int)(TIMER_PERIOD * 0.4);//Initialize compare mode to generate PWM2Timer_A_initCompareMode(TIMER_A0_BASE, &htim_PWM);htim_PWM.compareRegister = TIMER_A_CAPTURECOMPARE_REGISTER_3;htim_PWM.compareValue = (int)(TIMER_PERIOD * 0.6);//Initialize compare mode to generate PWM3Timer_A_initCompareMode(TIMER_A0_BASE, &htim_PWM);htim_PWM.compareRegister = TIMER_A_CAPTURECOMPARE_REGISTER_4;htim_PWM.compareValue = (int)(TIMER_PERIOD * 0.8);//Initialize compare mode to generate PWM4Timer_A_initCompareMode(TIMER_A0_BASE, &htim_PWM);}

依次將TA0.1、TA0.2、TA0.3、TA0.4初始化為占空比20%、40%、60%、80%，
時鐘源為SMCLK = 25MHz
分頻系數為40
裝載值為12500 - 1
故所得PWM頻率為25MHz/40/12500=50Hz

實驗結果

3.對稱PWM信號的產生

初始化程序

將上一個程稍作修改，即可產生對稱PWM信號
其中compareOutputMode值的效果參考下圖

時鐘源為SMCLK = 25MHz
分頻系數為40
裝載值為12500 - 1
因采用增\減計數模式
故所得PWM頻率為25MHz/40/12500/2=25Hz

#define TIMER_PERIOD 12500 void Timer_A_PWM_Init(void) {GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P1, GPIO_PIN2|GPIO_PIN3|GPIO_PIN4|GPIO_PIN5);Timer_A_initUpDownModeParam htim = {0};htim.clockSource = TIMER_A_CLOCKSOURCE_SMCLK;htim.clockSourceDivider = TIMER_A_CLOCKSOURCE_DIVIDER_40;htim.timerPeriod = TIMER_PERIOD - 1;htim.timerInterruptEnable_TAIE = TIMER_A_TAIE_INTERRUPT_DISABLE;htim.captureCompareInterruptEnable_CCR0_CCIE = TIMER_A_CCIE_CCR0_INTERRUPT_DISABLE;htim.timerClear = TIMER_A_DO_CLEAR;htim.startTimer = true;Timer_A_initUpDownMode(TIMER_A0_BASE, &htim);Timer_A_initCompareModeParam htim_PWM = {0};htim_PWM.compareInterruptEnable = TIMER_A_CAPTURECOMPARE_INTERRUPT_DISABLE;htim_PWM.compareOutputMode = TIMER_A_OUTPUTMODE_TOGGLE_RESET;htim_PWM.compareRegister = TIMER_A_CAPTURECOMPARE_REGISTER_1;htim_PWM.compareValue = (int)(TIMER_PERIOD * 0.2);//Initialize compare mode to generate PWM1Timer_A_initCompareMode(TIMER_A0_BASE, &htim_PWM);htim_PWM.compareRegister = TIMER_A_CAPTURECOMPARE_REGISTER_2;htim_PWM.compareValue = (int)(TIMER_PERIOD * 0.4);//Initialize compare mode to generate PWM2Timer_A_initCompareMode(TIMER_A0_BASE, &htim_PWM);htim_PWM.compareRegister = TIMER_A_CAPTURECOMPARE_REGISTER_3;htim_PWM.compareValue = (int)(TIMER_PERIOD * 0.6);//Initialize compare mode to generate PWM3Timer_A_initCompareMode(TIMER_A0_BASE, &htim_PWM);htim_PWM.compareRegister = TIMER_A_CAPTURECOMPARE_REGISTER_4;htim_PWM.compareValue = (int)(TIMER_PERIOD * 0.8);//Initialize compare mode to generate PWM4Timer_A_initCompareMode(TIMER_A0_BASE, &htim_PWM); }

實驗結果

總結

以上是生活随笔為你收集整理的MSP430F5529 DriverLib 库函数学习笔记（六）定时器A产生PWM波的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。