STM32用PWM输出驱动舵机的怪现象,求高手指导
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最近在编用STM32驱动舵机的程序,但在应用中发现一个非常怪的现象。 STM32端口初始化和PWM设置的程序如下:
端口初始化: RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC,ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOC, &GPIO_InitStructure);
PWM设置的程序如下:
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_TimeBaseStructure.TIM_Period = 20000; TIM_TimeBaseStructure.TIM_Prescaler = 71; TIM_TimeBaseStructure.TIM_ClockDivision = 0; TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); TIM3->CCMR1|=7<<4; TIM3->CCMR1|=1<<3; TIM3->CCER|=1<<0; TIM3->CR1=0x8000; TIM3->CCR1 = 2000;
TIM3->CCMR1|=7<<12; TIM3->CCMR1|=1<<11; TIM3->CCER|=1<<4; TIM3->CCR2 = 1600; TIM3->CR1=0x8000;
TIM3->CCMR2|=7<<4; TIM3->CCMR2|=1<<3; TIM3->CCER|=1<<8; TIM3->CCR3 = 1200; TIM3->CR1=0x8000;
TIM3->CCMR2|=7<<12; TIM3->CCMR2|=1<<11; TIM3->CCER|=1<<12; TIM3->CCR4 = 1000; TIM3->CR1=0x8000;
TIM3->CR1|=0x01; /* TIM enable counter */ TIM_CtrlPWMOutputs(TIM3,ENABLE);
现在的现象是,当我改变TIM3->CCR1 = 2000;这一行的值的时候,可以用示波器看到输出波形在变化,但舵机却始终只运行到一个固定的位置,就不再动了。这个位置也不随TIM3->CCR1的值变化而变动。
找了半天没找到原因,也百思不得其解,
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