F103RBT6串口与PWM输出问题

wwxn

要求需要同时开启串口二的输入功能以及PA2的PWM输出功能，但是当开启USART2的时钟时，PA2便无法输出PWM，请问如何解决？初始化代码如下：
串口输入：
[mw_shl_code=c,true]#include "main.h"

void STM_EVAL_COMInit(USART_InitTypeDef* USART_InitStruct)
{
    GPIO_InitTypeDef GPIO_InitStructure;

    /* Enable GPIO clock */
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);

    /* Configure USART Rx as input floating */
       
    GPIO_InitStructure.GPIO_Pin=GPIO_Pin_3;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    /* USART configuration */
    USART_Init(USART2, USART_InitStruct);

    /* Enable USART */
    USART_Cmd(USART2, ENABLE);
}




void USART2_Init(void)
{
    USART_InitTypeDef USART_InitStructure;
    NVIC_InitTypeDef NVIC_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;


    STM_EVAL_COMInit( &USART_InitStructure);
    USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);

    /* Enable the USARTz Interrupt */
    NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 4;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
}

u8 RX_Buffer[50];
u8 RX_Number;
void USART2_IRQHandler(void)
{
    if(USART_GetITStatus(USART2, USART_IT_RXNE) != RESET)
    {
        USART_ClearITPendingBit(USART2,USART_IT_RXNE);
        RX_Buffer[RX_Number++]=USART_ReceiveData(USART2);
    }
}[/mw_shl_code]
PWM输出：
[mw_shl_code=c,true]#include "main.h"

void PWM_OutputInit(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
       
    TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
    TIM_OCInitTypeDef  TIM_OCInitStructure;
    /* TIM3 clock enable */
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

    /* GPIOA and GPIOB clock enable */
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA |  RCC_APB2Periph_AFIO, ENABLE);


    /*GPIOB Configuration: TIM3 channel1, 2, 3 and 4 */
    GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_1  ;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

    GPIO_Init(GPIOA, &GPIO_InitStructure);
       
        /*GPIOB Configuration: TIM3 channel2 */
    GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_2 ;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

    GPIO_Init(GPIOA, &GPIO_InitStructure);


    /* Time base configuration */
    TIM_TimeBaseStructure.TIM_Period = 1000-1;
    TIM_TimeBaseStructure.TIM_Prescaler = 71;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

    /* PWM1 Mode configuration: Channel1 */
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = PWM2_ZKB*10;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

    TIM_OC2Init(TIM2, &TIM_OCInitStructure);

    TIM_OC2PreloadConfig(TIM2, TIM_OCPreload_Enable);

    /* PWM1 Mode configuration: Channel2 */
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = PWM1_ZKB*10;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

    TIM_OC3Init(TIM2, &TIM_OCInitStructure);

    TIM_OC3PreloadConfig(TIM2, TIM_OCPreload_Enable);
       
    TIM_ARRPreloadConfig(TIM2, ENABLE);

    /* TIM3 enable counter */
    TIM_Cmd(TIM2, ENABLE);
}

[/mw_shl_code]

正点原子

无法实现，换其他IO输出PWM，或者换其他IO做串口