stm32通用定时器的PWM输出

时间：2018-11-30 16:00:01

关键字： pwm输出 STM32 通用定时器

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[导读]配置过程：（以TIM3为例，其CH1-CH4为：PA6、PA7、PB0、PB1）1）开启TIM3时钟，配置4个IO口为复用推挽输出。2）设置TIM3的ARR和PSC来控制PWM的周期。3）设置TIM3的CH1-CH4的PWM模式及通道方向，使能TIM3的CH1-CH4输出

配置过程：（以TIM3为例，其CH1-CH4为：PA6、PA7、PB0、PB1）

1）开启TIM3时钟，配置4个IO口为复用推挽输出。

2）设置TIM3的ARR和PSC来控制PWM的周期。

3）设置TIM3的CH1-CH4的PWM模式及通道方向，使能TIM3的CH1-CH4输出。

4）使能TIM3。

程序如下：

/*
* 函数名：TIM3_GPIO_Config
* 描述：配置TIM3复用输出PWM时用到的I/O
* 输入：无
* 输出：无
* 调用：内部调用
*/
void TIM3_GPIO_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;

//PCLK1经过2倍频后作为TIM3的时钟源等于72MHz
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //开启TIM3时钟

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB, ENABLE);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; // 复用推挽输出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1;
GPIO_Init(GPIOB, &GPIO_InitStructure);
}

/*
* 函数名：TIM3_Mode_Config
* 描述：配置TIM3输出的PWM信号的模式，如周期、极性、占空比
* 输入：无
* 输出：无
* 调用：内部调用
*/
void TIM3_Mode_Config(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;

/* PWM信号电平跳变值 */
u16 CCR1_Val = 500;
u16 CCR2_Val = 375;
u16 CCR3_Val = 250;
u16 CCR4_Val = 125;

/* -----------------------------------------------------------------------
TIM3 Configuration: generate 4 PWM signals with 4 different duty cycles:
TIM3CLK = 72 MHz, Prescaler = 0x0, TIM3 counter clock = 72 MHz
TIM3 ARR Register = 999 => TIM3 Frequency = TIM3 counter clock/(ARR + 1)
TIM3 Frequency = 72 KHz.
TIM3 Channel1 duty cycle = (TIM3_CCR1/ TIM3_ARR)* 100 = 50% 500/(999+1)
TIM3 Channel2 duty cycle = (TIM3_CCR2/ TIM3_ARR)* 100 = 37.5%
TIM3 Channel3 duty cycle = (TIM3_CCR3/ TIM3_ARR)* 100 = 25%
TIM3 Channel4 duty cycle = (TIM3_CCR4/ TIM3_ARR)* 100 = 12.5%
----------------------------------------------------------------------- */ //TIM3_ARR=(TIM_Period +1)
//TIM3_CCR1=TIM_Pulse

/* Time base configuration */ //具体定时时间设置在后面
TIM_TimeBaseStructure.TIM_Period = 999; //当定时器从0计数到999，即为1000次，为一个定时周期
TIM_TimeBaseStructure.TIM_Prescaler = 0; //设置预分频：不预分频，即为72MHz
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1 ;//设置时钟分频系数：不分频
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //向上计数模式
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

/* PWM1 Mode configuration: Channel1 */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //配置为PWM模式1
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR1_Val; //设置跳变值，当计数器计数到这个值时，电平发生跳变
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //当定时器计数值小于CCR1_Val时为高电平
TIM_OC1Init(TIM3, &TIM_OCInitStructure); //使能通道1
TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);

/* PWM1 Mode configuration: Channel2 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR2_Val; //设置通道2的电平跳变值，输出另外一个占空比的PWM
TIM_OC2Init(TIM3, &TIM_OCInitStructure); //使能通道2
TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);

/* PWM1 Mode configuration: Channel3 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR3_Val; //设置通道3的电平跳变值，输出另外一个占空比的PWM
TIM_OC3Init(TIM3, &TIM_OCInitStructure); //使能通道3
TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable);

/* PWM1 Mode configuration: Channel4 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR4_Val; //设置通道4的电平跳变值，输出另外一个占空比的PWM
TIM_OC4Init(TIM3, &TIM_OCInitStructure); //使能通道4
TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable);

TIM_ARRPreloadConfig(TIM3, ENABLE); // 使能TIM3重载寄存器ARR

/* TIM3 enable counter */
TIM_Cmd(TIM3, ENABLE); //使能定时器3
}

/*
* 函数名：TIM3_PWM_Init
* 描述：TIM3 输出PWM信号初始化，只要调用这个函数
* TIM3的四个通道就会有PWM信号输出
* 输入：无
* 输出：无
* 调用：外部调用
*/
void TIM3_PWM_Init(void)
{
TIM3_GPIO_Config();
TIM3_Mode_Config();
}