STM32 通过定时器产生PPM信号

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void ppm_GPIO_Init(void)
{
  	GPIO_InitTypeDef GPIO_InitStructure;
 	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);
  
	GPIO_InitStructure.GPIO_Pin  = GPIO_Pin_0 ;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; 
  	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;  //ÍÆÍìÊä³ö50MHZ
 	GPIO_Init(GPIOA, &GPIO_InitStructure);
}


/**
  * @brief  基本定时器初始化，用于非阻塞延时用.
  * @param  None
  * @retval None
  */
void Timer_PPM_Tim5_Init(void)
{
    TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
    
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5, ENABLE); //时钟使能
    TIM_TimeBaseStructure.TIM_Period = 999;   //499 == 5 ms 中断一次 
    TIM_TimeBaseStructure.TIM_Prescaler = 71; // 
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM5, &TIM_TimeBaseStructure);
    TIM_ClearFlag(TIM5, TIM_FLAG_Update);
    //	TIM_ARRPreloadConfig(TIM7, DISABLE);
    TIM_ITConfig(TIM5, TIM_IT_Update, ENABLE);

    TIM_Cmd(TIM5, ENABLE);
}

u16 ppm_value = 0;

void Timer_PPM_Tim5_Time(u16 *timer)
{
	ppm_value = *timer;
	TIM_SetAutoreload(TIM5,*timer);
}

void Timer_PPM_Tim5_Start(void)
{
    TIM_ClearFlag(TIM5, TIM_FLAG_Update);
    TIM_ITConfig(TIM5, TIM_IT_Update, ENABLE);
    TIM_Cmd(TIM5, ENABLE);
}

void Timer_PPM_Tim5_Stop(void)
{
    TIM_ITConfig(TIM5, TIM_IT_Update, DISABLE);
    TIM_Cmd(TIM5, DISABLE);
}


void TIM_PPM_Init(void)
{
	ppm_GPIO_Init();
	Timer_PPM_Tim5_Init();
}



void TIM5_IRQHandler(void)
{
	if (TIM_GetITStatus(TIM5, TIM_IT_Update) != RESET)
	{
		ppm_out_process();
		TIM_ClearITPendingBit(TIM5, TIM_FLAG_Update);
	}
}

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#ifndef __TIM_PPM_H
#define __TIM_PPM_H

#define PPM_PIN PAout(0)

void TIM_PPM_Init(void);
void Timer_PPM_Tim5_Start(void);
void Timer_PPM_Tim5_Stop(void);
void Timer_PPM_Tim5_Time(u16 *timer);

#endif

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/*******************************************************************************
 * *****************************************************************************
 * 该部分功能实现需要开起一个1us中断一次的定时器，ppm_out_process()函数放在定时
 * 中断函数里面。
 * 主程序调用该函数ppm_MarkProcess()实现ppm数据的更新
 * 实现原理将：PPM理论上可以容纳10通道，但是有起始头等操作。所以占用一个通道的
 * 处理。最大也就容纳9个通道。根据通道的上升沿和下降沿找到20个标志时间点做跳变
 * 处理，输出PPM信号.
 * ****************************************************************************
 * ****************************************************************************/
#include "includes.h"

#define PPM_OUT_L 0
#define PPM_OUT_H 1

#define PPM_CH_NUB 8 //ppm通道数
#define PPM_FLAG_SPOT_NUB  18 //(PPM_CH_NUB *2 + 2)
#define PPM_CYCLE_TIME 20000 //us //50hz
#define PPM_LOW_TIME 400 //us


#define LOCK 	1
#define UNLOCK 	0

u8 Lock = UNLOCK;
u16 ppm_data_flag[PPM_FLAG_SPOT_NUB];

PPM_Struct PPM = {
    ppm_init,
    ppm_out_process, //定时器回调函数
    ppm_MarkProcess,
    NULL,
    NULL,
};

PPM_Bottom_Struct PPM_Bottom = {
    &PPM_PIN,
    TIM_PPM_Init,
    Timer_PPM_Tim5_Time,
    Timer_PPM_Tim5_Start,
    Timer_PPM_Tim5_Stop,
};

//ppm数据初始化
void ppm_init(void)
{
    u8 i;
    for (i = 0; i < PPM_CH_NUB + 1; i ++)
    {
        ppm_data_flag[i * 2 + 1] = PPM_LOW_TIME;
    }

    PPM_Bottom.Init();
    *(PPM_Bottom.PPM_OUT_PIN) = PPM_OUT_L;
    Delay_ms(1000);
}

//ppm输出处理
void ppm_out_process(void)
{
    static u8 state = 0;
    //TIM_SetAutoreload(TIM5,ppm_data_flag[state]);
    PPM_Bottom.Time(&ppm_data_flag[state]);
    *(PPM_Bottom.PPM_OUT_PIN) = ~*(PPM_Bottom.PPM_OUT_PIN);
    state += 1;
    state %= PPM_FLAG_SPOT_NUB;
}

//ppm数据输入填充处理
void ppm_MarkProcess(u16 *buf)
{
    u16 *p = &ppm_data_flag[2];
    //u32 cycleTime_flag_time = PPM_HERAD_TIME;
    u32 cycleTime_flag_time = 0;
    u8 i;

    Lock = LOCK;
    for(i = 0; i < PPM_CH_NUB; i ++)
    {
        cycleTime_flag_time += buf[i];
        p[i * 2] = buf[i] - PPM_LOW_TIME;
    }
    ppm_data_flag[0] = PPM_CYCLE_TIME - cycleTime_flag_time - PPM_LOW_TIME;
    Lock = UNLOCK;
    p = NULL;	
}

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#ifndef __PPM_H_
#define __PPM_H_

//ppm 对外调用接口
typedef struct
{
	void (*Init)(void);
	void (*Out_process)(void);
	void (*MarkProcess)(u16 *buf);
	void (*Start)(void);
	void (*Stop)(void);
}PPM_Struct;

//ppm 底层接口
typedef struct
{
	volatile unsigned long *PPM_OUT_PIN;
	void (*Init)(void);
	void (*Time)(u16 *timer);
	void (*Start)(void);
	void (*Stop)(void);
}PPM_Bottom_Struct;

extern PPM_Struct PPM;

void ppm_init(void);
void ppm_out_process(void);
void ppm_MarkProcess(u16 *buf);
#endif