void USART_Config(void) //这是我配置USART2的函数,可以看到没有配置PA2
{
USART_InitTypeDef USART_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA, &GPIO_InitStructure);
USART_InitStructure.USART_BaudRate =9600;
USART_InitStructure.USART_WordLength = USART_WordLength_8b;
USART_InitStructure.USART_StopBits = USART_StopBits_1;
USART_InitStructure.USART_Parity = USART_Parity_No;
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_InitStructure.USART_Mode = USART_Mode_Rx;
USART_Init(USART2, &USART_InitStructure);
USART_ITConfig(USART2,USART_IT_RXNE,ENABLE);
USART_Cmd(USART2, ENABLE);
}
void TIM_Config(void) //配置TIM,PA1正常,PA2无法使用,在主函数中注释掉USART_Config()后PA2就可以正常输出PWM波了
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1 | GPIO_Pin_2;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOA, &GPIO_InitStructure);
TIM_TimeBaseInitStructure.TIM_Period = 999;
TIM_TimeBaseInitStructure.TIM_Prescaler = 71;
TIM_TimeBaseInitStructure.TIM_ClockDivision = 0;
TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM2,&TIM_TimeBaseInitStructure);
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_Pulse = Pulse2;
TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
TIM_OCInitStructure.TIM_OutputState = ENABLE;
TIM_OCInitStructure.TIM_OutputNState = ENABLE;
TIM_OC2Init(TIM2,&TIM_OCInitStructure);
TIM_OCInitStructure.TIM_Pulse = Pulse3;
TIM_OC3Init(TIM2,&TIM_OCInitStructure);
TIM_SetCompare2(TIM2, 0);
TIM_SetCompare3(TIM2, 0);
TIM_Cmd(TIM2, ENABLE);
TIM_CtrlPWMOutputs(TIM2, ENABLE);
}
十分不解
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