stm32通过串口控制电机程序

下面是一个简单的示例代码，通过串口控制电机的转速：

#include "stm32f10x.h"
#include <stdio.h>

#define USART_BAUDRATE 9600
#define BAUD_PRESCALER ((SystemCoreClock/2)/USART_BAUDRATE)

void USART1_Init(void);
void USART1_SendChar(char ch);
void USART1_SendString(const char *str);
char USART1_ReceiveChar(void);

void PWM_Init(void);
void Set_DutyCycle(uint16_t dutyCycle);

int main(void)
{
    USART1_Init();
    PWM_Init();
    
    uint16_t dutyCycle = 0;
    char buffer[10];
    
    while(1)
    {
        char command = USART1_ReceiveChar();
        
        if(command == 'f') // Forward
        {
            dutyCycle += 10;
            if(dutyCycle > 1000) dutyCycle = 1000;
            Set_DutyCycle(dutyCycle);
            sprintf(buffer, "%d", dutyCycle);
            USART1_SendString("Duty cycle: ");
            USART1_SendString(buffer);
            USART1_SendString("\r\n");
        }
        else if(command == 's') // Stop
        {
            dutyCycle = 0;
            Set_DutyCycle(dutyCycle);
            USART1_SendString("Stop\r\n");
        }
        else if(command == 'b') // Backward
        {
            dutyCycle -= 10;
            if(dutyCycle < -1000) dutyCycle = -1000;
            Set_DutyCycle(-dutyCycle);
            sprintf(buffer, "%d", -dutyCycle);
            USART1_SendString("Duty cycle: ");
            USART1_SendString(buffer);
            USART1_SendString("\r\n");
        }
    }
}

void USART1_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
    
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_USART1, ENABLE);
    
    // Configure USART1 Tx (PA9) as alternate function push-pull
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
    
    // Configure USART1 Rx (PA10) as input floating
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
    
    // Configure USART1
    USART_InitStructure.USART_BaudRate = USART_BAUDRATE;
    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_Mode_Tx;
    USART_Init(USART1, &USART_InitStructure);
    
    // Enable USART1
    USART_Cmd(USART1, ENABLE);
}

void USART1_SendChar(char ch)
{
    while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
    USART_SendData(USART1, ch);
}

void USART1_SendString(const char *str)
{
    while(*str)
    {
        USART1_SendChar(*str++);
    }
}

char USART1_ReceiveChar(void)
{
    while(USART_GetFlagStatus(USART1, USART_FLAG_RXNE) == RESET);
    return USART_ReceiveData(USART1);
}

void PWM_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_OCInitTypeDef TIM_OCInitStructure;
    
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
    
    // Configure PB0 as alternate function push-pull
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &GPIO_InitStructure);
    
    // Configure TIM3
    TIM_TimeBaseStructure.TIM_Period = 999;
    TIM_TimeBaseStructure.TIM_Prescaler = 72 - 1;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
    
    // Configure TIM3 channel 3 as PWM output
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 0;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC3Init(TIM3, &TIM_OCInitStructure);
    TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable);
    
    // Enable TIM3
    TIM_Cmd(TIM3, ENABLE);
}

void Set_DutyCycle(uint16_t dutyCycle)
{
    TIM_SetCompare3(TIM3, dutyCycle);
}

在这个示例代码中，我们通过USART1接收串口指令，根据指令来控制电机的转速。我们使用TIM3的PWM输出来控制电机，通过改变占空比来改变电机的转速。例如，当接收到指令 'f' 时，我们增加占空比10，以增加电机的转速；当接收到指令 's' 时，我们将占空比设置为0，以停止电机；当接收到指令 'b' 时，我们减少占空比10，以反向电机转动。