stm32输出pwm的问题

1万 · 2021-2-23 15:59

使用STM32f103的tim1_ch1输出pwm，我在keil里面仿真时，PA8脚输出的波形是需要的方波波形，但是放到硬件时，我测芯片PA8脚值时，始终是0.25V，是什么问题呢

void TIM1_config(u32 Cycle)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
RCC_APB2PeriphclockCmd(RCC_APB2Periph_GPIOA|RCC_APB2Periph_TIM1|RCC_APB2Periph_GPIOB , ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8; //TIM1_CH1 PA8
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);
TIM_TimeBaseStructure.TIM_Period = Cycle-1;
TIM_TimeBaseStructure.TIM_Prescaler =71;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
TIM_OCInitStructure.TIM_Pulse = Cycle/2-1;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
TIM_OC1Init(TIM1, &TIM_OCInitStructure);
TIM_SelectMasterSlaveMode(TIM1, TIM_MasterSlaveMode_Enable);
TIM_SelectOutputtrigger(TIM1, TIM_TRGOSource_Update);
TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable);
TIM_ARRPreloadConfig(TIM1, ENABLE);
}
void TIM4_config(u32 PulseNum)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
NVIC_InitTypeDef NVIC_InitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
TIM_TimeBaseStructure.TIM_Period = PulseNum-1;
TIM_TimeBaseStructure.TIM_Prescaler =0;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);
TIM_SelectInputTrigger(TIM4, TIM_TS_ITR0);
//TIM_InternalClockConfig(TIM4);
TIM4->SMCR|=0x07;
//TIM_ITRxExternalClockConfig(TIM4, TIM_TS_ITR0);
//TIM_ARRPreloadConfig(TIM4, ENABLE);
TIM_ITConfig(TIM4,TIM_IT_Update,DISABLE);
// NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3);
NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
void Pulse_output(u32 Cycle,u32 PulseNum)
{
TIM4_config(PulseNum);
TIM_Cmd(TIM4, ENABLE);
TIM_ClearITPendingBit(TIM4,TIM_IT_Update);
TIM_ITConfig(TIM4,TIM_IT_Update,ENABLE);
TIM1_config(Cycle);
TIM_Cmd(TIM1, ENABLE);
TIM_CtrlPWMOutputs(TIM1, ENABLE);
}
void TIM4_IRQHandler(void)
{
if (TIM_GetITStatus(TIM4, TIM_IT_Update) != RESET)
{
TIM_ClearITPendingBit(TIM4, TIM_IT_Update);
TIM_CtrlPWMOutputs(TIM1, DISABLE);
TIM_Cmd(TIM1, DISABLE);
TIM_Cmd(TIM4, DISABLE);
TIM_ITConfig(TIM4, TIM_IT_Update, DISABLE);
}
}