compare控制电机速度c语言代码

在C语言中，可以使用比较器来控制电机的速度。具体的代码实现需要根据你使用的电机驱动板和单片机型号而定。下面是一个简单的示例代码，假设使用的是STM32F103C8T6单片机和L298N电机驱动板：

#include "stm32f10x.h"

#define MOTOR_PIN1 GPIO_Pin_0
#define MOTOR_PIN2 GPIO_Pin_1
#define MOTOR_PIN3 GPIO_Pin_2
#define MOTOR_PIN4 GPIO_Pin_3

void TIM2_Configuration(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
    TIM_OCInitTypeDef TIM_OCInitStruct;
    
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    
    GPIO_InitTypeDef GPIO_InitStruct;
    GPIO_InitStruct.GPIO_Pin = MOTOR_PIN1 | MOTOR_PIN2 | MOTOR_PIN3 | MOTOR_PIN4;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStruct);
    
    TIM_TimeBaseInitStruct.TIM_Prescaler = 71;
    TIM_TimeBaseInitStruct.TIM_Period = 999;
    TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStruct);
    
    TIM_OCInitStruct.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStruct.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStruct.TIM_Pulse = 0;
    TIM_OCInitStruct.TIM_OCPolarity = TIM_OCPolarity_High;
    
    TIM_OC1Init(TIM2, &TIM_OCInitStruct);
    TIM_OC2Init(TIM2, &TIM_OCInitStruct);
    TIM_OC3Init(TIM2, &TIM_OCInitStruct);
    TIM_OC4Init(TIM2, &TIM_OCInitStruct);
    
    TIM_Cmd(TIM2, ENABLE);
}

void set_motor_speed(int speed)
{
    if (speed > 0)
    {
        GPIO_SetBits(GPIOA, MOTOR_PIN1);
        GPIO_ResetBits(GPIOA, MOTOR_PIN2);
        GPIO_SetBits(GPIOA, MOTOR_PIN3);
        GPIO_ResetBits(GPIOA, MOTOR_PIN4);
        TIM_SetCompare1(TIM2, speed);
        TIM_SetCompare2(TIM2, 0);
        TIM_SetCompare3(TIM2, speed);
        TIM_SetCompare4(TIM2, 0);
    }
    else if (speed < 0)
    {
        GPIO_ResetBits(GPIOA, MOTOR_PIN1);
        GPIO_SetBits(GPIOA, MOTOR_PIN2);
        GPIO_ResetBits(GPIOA, MOTOR_PIN3);
        GPIO_SetBits(GPIOA, MOTOR_PIN4);
        TIM_SetCompare1(TIM2, 0);
        TIM_SetCompare2(TIM2, -speed);
        TIM_SetCompare3(TIM2, 0);
        TIM_SetCompare4(TIM2, -speed);
    }
    else
    {
        GPIO_ResetBits(GPIOA, MOTOR_PIN1);
        GPIO_ResetBits(GPIOA, MOTOR_PIN2);
        GPIO_ResetBits(GPIOA, MOTOR_PIN3);
        GPIO_ResetBits(GPIOA, MOTOR_PIN4);
        TIM_SetCompare1(TIM2, 0);
        TIM_SetCompare2(TIM2, 0);
        TIM_SetCompare3(TIM2, 0);
        TIM_SetCompare4(TIM2, 0);
    }
}

int main(void)
{
    TIM2_Configuration();
    
    while (1)
    {
        set_motor_speed(100); // 设置电机速度为正100
    }
}

在上面的代码中，我们使用了STM32F103C8T6单片机的定时器TIM2来控制电机的速度。通过调整定时器的输出比较寄存器（TIMx_CCRy）的值，可以改变电机的占空比，从而控制电机的转速。具体实现方式可以参考代码中的set_motor_speed函数。