stm32f103按键控制电机转速实验内容

实验目的：使用STM32F103单片机控制直流电机转速，并通过按键控制电机的转速。

实验器材：STM32F103C8T6开发板、直流电源、直流电机、按键开关、杜邦线等。

实验原理：通过PWM输出控制电机的转速，按键控制占空比的变化，从而改变电机的转速。

实验步骤：

1. 将STM32F103C8T6开发板与直流电机连接，电源接入开发板的5V和GND端口，电机的正极接入开发板的PA6口，电机的负极接入开发板的GND端口。

2. 将按键连接到开发板的PC13口，其中一个端口接入PC13口，另一个端口接入GND端口。

3. 配置开发板的PWM输出，将PA6口配置为TIM3_CH1输出，使用TIM3作为PWM输出的定时器。具体配置方法可以参考STM32的官方文档和开发板的手册。

4. 配置开发板的中断服务函数，当按键按下时，改变PWM的占空比，从而改变电机的转速。具体代码实现可以参考下面的示例代码。

5. 编写主函数，初始化开发板的各个模块，并进入循环中等待按键的触发。

示例代码：

#include "stm32f10x.h"
#include "stm32f10x_gpio.h"
#include "stm32f10x_rcc.h"
#include "stm32f10x_tim.h"

#define MOTOR_PWM_TIM TIM3
#define MOTOR_PWM_PIN GPIO_Pin_6
#define MOTOR_PWM_GPIO GPIOA
#define MOTOR_PWM_TIM_CLK RCC_APB1Periph_TIM3
#define MOTOR_PWM_GPIO_CLK RCC_APB2Periph_GPIOA

#define BUTTON_GPIO GPIOC
#define BUTTON_PIN GPIO_Pin_13
#define BUTTON_GPIO_CLK RCC_APB2Periph_GPIOC

void TIM_Configuration(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_OCInitTypeDef TIM_OCInitStructure;
    GPIO_InitTypeDef GPIO_InitStructure;

    /* TIM3 clock enable */
    RCC_APB1PeriphClockCmd(MOTOR_PWM_TIM_CLK, ENABLE);

    /* GPIOA clock enable */
    RCC_APB2PeriphClockCmd(MOTOR_PWM_GPIO_CLK, ENABLE);

    /* GPIOA Configuration: PA6 as alternate function push-pull */
    GPIO_InitStructure.GPIO_Pin = MOTOR_PWM_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

    GPIO_Init(MOTOR_PWM_GPIO, &GPIO_InitStructure);

    /* Time base configuration */
    TIM_TimeBaseStructure.TIM_Period = 999;
    TIM_TimeBaseStructure.TIM_Prescaler = 719;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

    TIM_TimeBaseInit(MOTOR_PWM_TIM, &TIM_TimeBaseStructure);

    /* PWM1 Mode configuration: Channel1 */
    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_OC1Init(MOTOR_PWM_TIM, &TIM_OCInitStructure);

    TIM_OC1PreloadConfig(MOTOR_PWM_TIM, TIM_OCPreload_Enable);

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

void EXTI_Configuration(void)
{
    EXTI_InitTypeDef EXTI_InitStructure;
    GPIO_InitTypeDef GPIO_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    /* GPIOC clock enable */
    RCC_APB2PeriphClockCmd(BUTTON_GPIO_CLK, ENABLE);

    /* Configure Button pin as input floating */
    GPIO_InitStructure.GPIO_Pin = BUTTON_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_Init(BUTTON_GPIO, &GPIO_InitStructure);

    /* Connect Button EXTI Line to Button GPIO Pin */
    GPIO_EXTILineConfig(GPIO_PortSourceGPIOC, GPIO_PinSource13);

    /* Configure Button EXTI line */
    EXTI_InitStructure.EXTI_Line = EXTI_Line13;
    EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
    EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
    EXTI_InitStructure.EXTI_LineCmd = ENABLE;

    EXTI_Init(&EXTI_InitStructure);

    /* Enable and set Button EXTI Interrupt to the lowest priority */
    NVIC_InitStructure.NVIC_IRQChannel = EXTI15_10_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0F;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x0F;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

    NVIC_Init(&NVIC_InitStructure);
}

int main(void)
{
    TIM_Configuration();
    EXTI_Configuration();

    while (1)
    {
        /* Do nothing */
    }
}

void EXTI15_10_IRQHandler(void)
{
    if (EXTI_GetITStatus(EXTI_Line13) != RESET)
    {
        static uint16_t pwm_value = 0;
        static uint8_t increase_pwm = 1;

        if (increase_pwm)
        {
            pwm_value += 100;
            if (pwm_value >= 1000)
            {
                increase_pwm = 0;
            }
        }
        else
        {
            pwm_value -= 100;
            if (pwm_value <= 0)
            {
                increase_pwm = 1;
            }
        }

        TIM_SetCompare1(MOTOR_PWM_TIM, pwm_value);

        EXTI_ClearITPendingBit(EXTI_Line13);
    }
}

实验注意事项：

1. 实验中要注意电机的正负极的接线，保证电机能够正常工作。

2. 在按键的中断服务函数中，要注意占空比的变化范围，避免电机转速变化过快或过慢。

3. 在编写代码时，要注意各个模块的初始化顺序和参数设置，保证程序能够正常运行。