stm32103c8t6核心板 时钟为8mhz 输出周期为20ms的pwm
时间: 2024-02-22 12:01:33 浏览: 16
好的,这是一个关于STM32F103C8T6核心板的PWM输出的问题。
首先,需要将时钟频率设置为8MHz。可以通过以下代码实现:
```c
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_TimeBaseStructure.TIM_Prescaler = 399;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseStructure.TIM_Period = 1999;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
TIM_OCInitTypeDef TIM_OCInitStructure;
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = 1000;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OC1Init(TIM2, &TIM_OCInitStructure);
TIM_Cmd(TIM2, ENABLE);
```
这里使用了TIM2作为计时器,GPIOA的Pin 0作为PWM输出口。时钟频率设置为8MHz,计时器预分频值为399,计时器周期为1999。所以计时器的计数频率为8MHz / (399 + 1) = 20kHz。PWM的周期为(1999 + 1) / 20kHz = 100ms,占空比可以通过修改TIM_OCInitStructure.TIM_Pulse的值来实现。例如,如果需要20ms的周期,占空比为50%,则可以将TIM_OCInitStructure.TIM_Pulse设置为(1999 + 1) * 50% / 20ms = 1000。
希望这能帮助你解决问题。