怎么用STM32配置產(chǎn)生PWM
STM32產(chǎn)生PWM是非常的方便的，要需要簡單的設(shè)置定時器，即刻產(chǎn)生！當(dāng)然，簡單的設(shè)置對于新手來講，也是麻煩的，主要包括：
（1）使能定時器時鐘：
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
（2）定義相應(yīng)的GPIO：
/* PA2,3,4,5,6輸出->Key_Up,Key_Down,Key_Left,Key_Right,Key_Ctrl */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_3|GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_6;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; //下拉接地，檢測輸入的高電平
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M時鐘速度
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* PA7用于發(fā)出PWM波,即無線數(shù)據(jù)傳送 */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M時鐘速度
GPIO_Init(GPIOA, &GPIO_InitStructure);
（3）如果是產(chǎn)生PWM（頻率不變，占空比可變），記得打開PWM控制，在TIM_Configuration()中。
TIM_Cmd(TIM3,ENABLE);
/* TIM1 Main Output Enable */
TIM_CtrlPWMOutputs(TIM1,ENABLE);
利用定時器產(chǎn)生不同頻率的PWM
有時候，需要產(chǎn)生不同頻率的PWM，這個時候，設(shè)置與產(chǎn)生相同PWM的程序，有關(guān)鍵的不一樣。
（一） 設(shè)置的原理
利用改變定時器輸出比較通道的捕獲值，當(dāng)輸出通道捕獲值產(chǎn)生中斷時，在中斷中將捕獲值改變，這時， 輸出的I/O會產(chǎn)生一個電平翻轉(zhuǎn)，利用這種辦法，實(shí)現(xiàn)不同頻率的PWM輸出。
（二）關(guān)鍵設(shè)置
在定時器設(shè)置中：
TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Disable);
在中斷函數(shù)中：
if (TIM_GetITStatus(TIM3, TIM_IT_CC2) != RESET)
{
TIM_ClearITPendingBit(TIM3, TIM_IT_CC2);
capture = TIM_GetCapture2(TIM3);
TIM_SetCompare2(TIM3, capture + Key_Value);
}
一個定時器四個通道，分別產(chǎn)生不同頻率（這個例子網(wǎng)上也有）
vu16 CCR1_Val = 32768;
vu16 CCR2_Val = 16384;
vu16 CCR3_Val = 8192;
vu16 CCR4_Val = 4096;
void TIM_Configuration(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
/* TIM2 clock enable */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
/* ---------------------------------------------------------------
TIM2 Configuration: Output Compare Toggle Mode:
TIM2CLK = 36 MHz, Prescaler = 0x2, TIM2 counter clock = 12 MHz
CC1 update rate = TIM2 counter clock / CCR1_Val = 366.2 Hz
CC2 update rate = TIM2 counter clock / CCR2_Val = 732.4 Hz
CC3 update rate = TIM2 counter clock / CCR3_Val = 1464.8 Hz
CC4 update rate = TIM2 counter clock / CCR4_Val = 2929.6 Hz
--------------------------------------------------------------- *//* Time base configuration */
TIM_TimeBaseStructure.TIM_Period = 65535;
TIM_TimeBaseStructure.TIM_Prescaler = 2;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);/* Channel 1 Configuration in PWM mode */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle; //PWM模式2
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //正向通道有效
TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Disable;//反向通道無效
TIM_OCInitStructure.TIM_Pulse = CCR1_Val; //占空時間
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //輸出極性
TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High; //互補(bǔ)端的極性
TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;TIM_OC1Init(TIM2,&TIM_OCInitStructure); //通道1
TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Disable);TIM_OCInitStructure.TIM_Pulse = CCR2_Val; //占空時間
TIM_OC2Init(TIM2,&TIM_OCInitStructure); //通道2
TIM_OC2PreloadConfig(TIM2, TIM_OCPreload_Disable);TIM_OCInitStructure.TIM_Pulse = CCR3_Val; //占空時間
TIM_OC3Init(TIM2,&TIM_OCInitStructure); //通道3
TIM_OC3PreloadConfig(TIM2, TIM_OCPreload_Disable);TIM_OCInitStructure.TIM_Pulse = CCR4_Val; //占空時間
TIM_OC4Init(TIM2,&TIM_OCInitStructure); //通道4
TIM_OC4PreloadConfig(TIM2, TIM_OCPreload_Disable);
/* TIM2 counter enable */
TIM_Cmd(TIM2,ENABLE);
/* TIM2 Main Output Enable */
//TIM_CtrlPWMOutputs(TIM2,ENABLE);/* TIM IT enable */
TIM_ITConfig(TIM2, TIM_IT_CC1 | TIM_IT_CC2 | TIM_IT_CC3 | TIM_IT_CC4, ENABLE);
}
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;/*允許總線CLOCK,在使用GPIO之前必須允許相應(yīng)端的時鐘.從STM32的設(shè)計(jì)角度上說,沒被允許的端將不接入時鐘,也就不會耗能,這是STM32節(jié)能的一種技巧,*/
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD, ENABLE);
/* PA2,3,4,5,6,7輸出->LED1,LED2,LED3,LED4,LED5,LED6 */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_3|GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_6|GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD; //開漏輸出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M時鐘速度
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* PB0,1輸出->LED7,LED8*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD; //開漏輸出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M時鐘速度
GPIO_Init(GPIOB, &GPIO_InitStructure);
/* PA0,1->KEY_LEFT,KEY_RIGHT*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; //上拉輸入
GPIO_Init(GPIOA, &GPIO_InitStructure);/* PC13->KEY_UP*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; //上拉輸入
GPIO_Init(GPIOC, &GPIO_InitStructure);/* PB5->KEY_DOWN*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; //上拉輸入
GPIO_Init(GPIOB, &GPIO_InitStructure);
/* GPIOA Configuration:TIM2 Channel1, 2, 3 and 4 in Output */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_3;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);
}
void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;/* Configure one bit for preemption priority */
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);NVIC_InitStructure.NVIC_IRQChannel=TIM2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority=1;
NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
u16 capture = 0;
extern vu16 CCR1_Val;
extern vu16 CCR2_Val;
extern vu16 CCR3_Val;
extern vu16 CCR4_Val;
void TIM2_IRQHandler(void)
{
/* TIM2_CH1 toggling with frequency = 183.1 Hz */
if (TIM_GetITStatus(TIM2, TIM_IT_CC1) != RESET)
{
TIM_ClearITPendingBit(TIM2, TIM_IT_CC1 );
capture = TIM_GetCapture1(TIM2);
TIM_SetCompare1(TIM2, capture + CCR1_Val );
}
/* TIM2_CH2 toggling with frequency = 366.2 Hz */
if (TIM_GetITStatus(TIM2, TIM_IT_CC2) != RESET)
{
TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);
capture = TIM_GetCapture2(TIM2);
TIM_SetCompare2(TIM2, capture + CCR2_Val);
}/* TIM2_CH3 toggling with frequency = 732.4 Hz */
if (TIM_GetITStatus(TIM2, TIM_IT_CC3) != RESET)
{
TIM_ClearITPendingBit(TIM2, TIM_IT_CC3);
capture = TIM_GetCapture3(TIM2);
TIM_SetCompare3(TIM2, capture + CCR3_Val);
}/* TIM2_CH4 toggling with frequency = 1464.8 Hz */
if (TIM_GetITStatus(TIM2, TIM_IT_CC4) != RESET)
{
TIM_ClearITPendingBit(TIM2, TIM_IT_CC4);
capture = TIM_GetCapture4(TIM2);
TIM_SetCompare4(TIM2, capture + CCR4_Val);
}}
一個定時器一個通道，產(chǎn)生不同頻率
其它的設(shè)置都一樣，就是在主函數(shù)中修改一個參數(shù)，然后在定時器中斷中，根據(jù)這個參數(shù)，改變頻率。
#include "stm32lib\stm32f10x.h"
#include "hal.h"volatile u16 Key_Value=1000; //用于保存按鍵相應(yīng)的PWM波占空比值
int main(void)
{
ChipHalInit();
ChipOutHalInit();while(1)
{
if( (!Get_Key_Up)&(!Get_Key_Down)&(!Get_Key_Left)&(!Get_Key_Right)&(!Get_Key_Ctrl) )
{
Key_Value=12000;
}
else
{
if(Get_Key_Up) //按鍵前進(jìn)按下 ,對應(yīng)1kHz
{
Key_Value=6000;
}
else if(Get_Key_Down) //按鍵后退按下 ,對應(yīng)2kHz
{
Key_Value=3000;
}
Delay_Ms(20); //10ms延時if(Get_Key_Left) //按鍵左轉(zhuǎn)按下,對應(yīng)3kHz
{
Key_Value=2000;
}
else if(Get_Key_Right) //按鍵右轉(zhuǎn)按下,對應(yīng)4kHz
{
Key_Value=1500;
}
Delay_Ms(20); //10ms延時if(Get_Key_Ctrl) //按鍵控制按下,對應(yīng)5kHz
{
Key_Value=1200;
}
Delay_Ms(20); //10ms延時
}
}
}extern volatile u16 Key_Value;
u16 capture=0;
void TIM3_IRQHandler(void)
{
/* TIM2_CH2 toggling with frequency = 366.2 Hz */
if (TIM_GetITStatus(TIM3, TIM_IT_CC2) != RESET)
{
TIM_ClearITPendingBit(TIM3, TIM_IT_CC2);
capture = TIM_GetCapture2(TIM3);
TIM_SetCompare2(TIM3, capture + Key_Value);
}
}void TIM3_Configuration(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;/* TIM2 clock enable */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);/*TIM1時鐘配置*/
TIM_TimeBaseStructure.TIM_Prescaler = 5; //預(yù)分頻(時鐘分頻)72M/6=12M
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //向上計(jì)數(shù)
TIM_TimeBaseStructure.TIM_Period = 65535; //裝載值選擇最大
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_RepetitionCounter = 0x0;
TIM_TimeBaseInit(TIM3,&TIM_TimeBaseStructure);/* Channel 1 Configuration in PWM mode */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle; //PWM模式2
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //正向通道有效
TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Disable;//反向通道無效
TIM_OCInitStructure.TIM_Pulse = Key_Value; //占空時間
TIM_OCInitStructure.TIM_OCPolarity =
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