stm32的sg90舵机代码

以下是使用STM32控制SG90舵机的示例代码：

#include "stm32f10x.h"

#define PWM_GPIO_PIN    GPIO_Pin_0
#define PWM_GPIO_PORT   GPIOA
#define PWM_TIM         TIM2

void PWM_Configuration(void);

int main(void)
{
    uint16_t pulse_width = 0;
    uint8_t direction = 0;

    PWM_Configuration();

    while(1)
    {
        if(direction == 0)
        {
            pulse_width += 10;
            if(pulse_width >= 180)
            {
                direction = 1;
            }
        }
        else
        {
            pulse_width -= 10;
            if(pulse_width <= 0)
            {
                direction = 0;
            }
        }

        TIM_SetCompare1(PWM_TIM, pulse_width);
        for(int i=0; i<1000000; i++);    //简单的延时
    }
}

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

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

    GPIO_InitStructure.GPIO_Pin = PWM_GPIO_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(PWM_GPIO_PORT, &GPIO_InitStructure);

    TIM_TimeBaseStructure.TIM_Period = 20000 - 1;    //20ms的周期，对应50Hz的频率
    TIM_TimeBaseStructure.TIM_Prescaler = 72 - 1;    //72MHz的系统时钟，预分频器设置为72，计数器时钟为1MHz
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(PWM_TIM, &TIM_TimeBaseStructure);

    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OCInitStructure.TIM_Pulse = 0;    //初始占空比为0
    TIM_OC1Init(PWM_TIM, &TIM_OCInitStructure);

    TIM_Cmd(PWM_TIM, ENABLE);
    TIM_CtrlPWMOutputs(PWM_TIM, ENABLE);
}

在这个示例中，我们使用了TIM2通道1来控制SG90舵机。我们设置了一个20ms的周期，对应50Hz的频率，这是SG90舵机的标准频率。然后我们按照占空比的变化来控制舵机的角度。占空比为0时，舵机转到最左边；占空比为180时，舵机转到最右边。在这个示例中，我们每次增加或减少10个计数器单位，然后等待一段简单的延时，以便我们可以看到舵机的运动。