用代码使用stm32标准库函数解析ppm信号

以下是使用STM32标准库函数解析PPM信号的示例代码：

#include "stm32f4xx.h"

#define PPM_CHANNEL_COUNT 8
#define PPM_FRAME_LENGTH 30000

volatile uint16_t ppm[PWM_CHANNEL_COUNT];

void TIM2_IRQHandler(void)
{
    static uint8_t current_channel = 0;
    static uint16_t last_time = 0;
    uint16_t current_time = TIM_GetCapture1(TIM2);
    uint16_t pulse_width = current_time - last_time;
    
    if (pulse_width > 1000) {
        current_channel = 0; // Start of new frame
    } else {
        ppm[current_channel] = pulse_width;
        current_channel++;
        if (current_channel >= PPM_CHANNEL_COUNT) {
            current_channel = 0; // End of frame
        }
    }
    
    last_time = current_time;
    
    TIM_ClearITPendingBit(TIM2, TIM_IT_CC1);
}

int main(void)
{
    // Initialize GPIO and timer
    GPIO_InitTypeDef GPIO_InitStructure;
    TIM_TimeBaseInitTypeDef TIM_TimeBase_InitStructure;
    TIM_ICInitTypeDef TIM_IC_InitStructure;
    
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
    
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource0, GPIO_AF_TIM2);
    
    TIM_TimeBase_InitStructure.TIM_Prescaler = 83; // Assuming 84 MHz clock, 1 MHz timer clock
    TIM_TimeBase_InitStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBase_InitStructure.TIM_Period = PPM_FRAME_LENGTH - 1;
    TIM_TimeBase_InitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBase_InitStructure);
    
    TIM_IC_InitStructure.TIM_Channel = TIM_Channel_1;
    TIM_IC_InitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
    TIM_IC_InitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
    TIM_IC_InitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
    TIM_IC_InitStructure.TIM_ICFilter = 0x0;
    TIM_ICInit(TIM2, &TIM_IC_InitStructure);
    
    TIM_ITConfig(TIM2, TIM_IT_CC1, ENABLE);
    NVIC_EnableIRQ(TIM2_IRQn);
    
    TIM_Cmd(TIM2, ENABLE);
    
    while (1) {
        // Process ppm array here
    }
}

此代码使用TIM2定时器来捕捉PPM信号的脉冲宽度，并将其存储在ppm数组中。每个通道的脉冲宽度将在TIM2的CC1中断中捕获和处理。在主循环中，您可以根据需要对ppm数组进行进一步处理