使用stm32来解析航模遥控器协议-平芜编程栈

前置知识：航模遥控器一般的协议有sbus，ppm，ibus，dbus等等，解析一般使用ppm协议

解析ppm协议最方便也最容易，解析sbus和dbus或者ibus，一般都需要硬件适配，或者是软件不方便解析，ppm直接一个gpio＋中断＋定时器就可以实现了，基本所有遥控器都有ppm协议

解析ppm协议：

利用上升沿触发外部中断（IO口默认下拉电平）
利用一个ms级定时器来记录相邻2次外部中断的触发时间间隔，即某个通道PWM的高电平持续时间，并在外部中断回调函数中，对记录的时间间隔进行判断：如果小于等于2ms，说明是某个通道的PWM高电平持续时间；反之即是同步时间，此时，说明PPM信号一个周期已经结束。

1.遥控器配置（最重要一步）设置ppm协议

先把协议换成ppm协议，有些一开始不是默认ppm，是wbus或者其他，需要我们配置ok

2.设置遥控器通道

我们可以在这里实现通道的变换，前面四个通道建议不换，更换后面俩个，改变后面俩个就表示，第五个通道数据是sc来控制，第六个是sd来控制

3.选择可以实现gpio外部中断的，随便一个引脚

gpio设置为下降沿检测，和上拉模式

gpio的中断向量也打开

gpio这一步就算是配置好了，这个gpio是用来接收ppm信号线的

2.配置定时器，随便一个定时器，可以实现定时功能即可

中断向量也打开

预分频器自己计算，我的是f103，72mh直接拉满了

4.然后就配置完成了，在stm32cbuemx就算是完成了，下来是添加ppm解析代码

1.ppm.c

#include "ppm.h" #include "tim.h" uint16_t ppm_ch[PPM_CHN_MAX] = {0}; static uint16_t last_capt = 0; // 修复变量名，移除空格 static uint8_t chn_idx = 0; uint8_t ppm_ready = 0; /* PPM模块初始化 */ void ppm_init(void) { // 启动TIM2定时器用于时间测量 HAL_TIM_Base_Start(&htim2); // 确保TIM2计数器清零 __HAL_TIM_SET_COUNTER(&htim2, 0); // 初始化变量 last_capt = 0; chn_idx = 0; ppm_ready = 0; // 清零所有通道数据 for(int i = 0; i < PPM_CHN_MAX; i++) { ppm_ch[i] = 0; } } /* 下降沿中断回调，CubeMX 已自动生成入口 */ void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin) { if(GPIO_Pin != GPIO_PIN_10) return; uint16_t now = TIM2->CNT; // 读当前 1 µs 计数 uint16_t dt = now - last_capt; // 计算与上次下降沿间隔 last_capt = now; if(dt >= 4000) // 同步脉冲 ≥4 ms → 新帧开始 { chn_idx = 0; ppm_ready = 1; // 通知主循环"帧已齐" return; } if(chn_idx < PPM_CHN_MAX) // 存储通道脉宽 { ppm_ch[chn_idx++] = dt; } }

2.ppm.h

#ifndef __PPM_H #define __PPM_H #ifdef __cplusplus extern "C" { #endif #include "main.h" #define PPM_CHN_MAX 6 // 通道数 extern uint16_t ppm_ch[PPM_CHN_MAX]; // 单位 µs extern uint8_t ppm_ready; // 1=新一帧已解析完 void ppm_init(void); // PPM模块初始化函数 #ifdef __cplusplus } #endif #endif

3.main函数

/* USER CODE BEGIN Header */ /** ****************************************************************************** * @file : main.c * @brief : Main program body ****************************************************************************** * @attention * * Copyright (c) 2026 STMicroelectronics. * All rights reserved. * * This software is licensed under terms that can be found in the LICENSE file * in the root directory of this software component. * If no LICENSE file comes with this software, it is provided AS-IS. * ****************************************************************************** */ /* USER CODE END Header */ /* Includes ------------------------------------------------------------------*/ #include "main.h" #include "tim.h" #include "gpio.h" #include "ppm.h" /* Private includes ----------------------------------------------------------*/ /* USER CODE BEGIN Includes */ /* USER CODE END Includes */ /* Private typedef -----------------------------------------------------------*/ /* USER CODE BEGIN PTD */ /* USER CODE END PTD */ /* Private define ------------------------------------------------------------*/ /* USER CODE BEGIN PD */ /* USER CODE END PD */ /* Private macro -------------------------------------------------------------*/ /* USER CODE BEGIN PM */ /* USER CODE END PM */ /* Private variables ---------------------------------------------------------*/ /* USER CODE BEGIN PV */ /* USER CODE END PV */ /* Private function prototypes -----------------------------------------------*/ void SystemClock_Config(void); /* USER CODE BEGIN PFP */ /* USER CODE END PFP */ /* Private user code ---------------------------------------------------------*/ /* USER CODE BEGIN 0 */ /* USER CODE END 0 */ /** * @brief The application entry point. * @retval int */ int main(void) { /* USER CODE BEGIN 1 */ /* USER CODE END 1 */ /* MCU Configuration--------------------------------------------------------*/ /* Reset of all peripherals, Initializes the Flash interface and the Systick. */ HAL_Init(); /* USER CODE BEGIN Init */ /* USER CODE END Init */ /* Configure the system clock */ SystemClock_Config(); /* USER CODE BEGIN SysInit */ /* USER CODE END SysInit */ /* Initialize all configured peripherals */ MX_GPIO_Init(); MX_TIM2_Init(); ppm_init(); /* USER CODE BEGIN 2 */ /* USER CODE END 2 */ /* Infinite loop */ /* USER CODE BEGIN WHILE */ while (1) { /* USER CODE END WHILE */ if (ppm_ready) { ppm_ready = 0; } /* USER CODE BEGIN 3 */ } /* USER CODE END 3 */ } /** * @brief System Clock Configuration * @retval None */ void SystemClock_Config(void) { RCC_OscInitTypeDef RCC_OscInitStruct = {0}; RCC_ClkInitTypeDef RCC_ClkInitStruct = {0}; /** Initializes the RCC Oscillators according to the specified parameters * in the RCC_OscInitTypeDef structure. */ RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE; RCC_OscInitStruct.HSEState = RCC_HSE_ON; RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1; RCC_OscInitStruct.HSIState = RCC_HSI_ON; RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON; RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE; RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9; if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) { Error_Handler(); } /** Initializes the CPU, AHB and APB buses clocks */ RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2; RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK; RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1; RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2; RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1; if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK) { Error_Handler(); } } /* USER CODE BEGIN 4 */ /* USER CODE END 4 */ /** * @brief This function is executed in case of error occurrence. * @retval None */ void Error_Handler(void) { /* USER CODE BEGIN Error_Handler_Debug */ /* User can add his own implementation to report the HAL error return state */ __disable_irq(); while (1) { } /* USER CODE END Error_Handler_Debug */ } #ifdef USE_FULL_ASSERT /** * @brief Reports the name of the source file and the source line number * where the assert_param error has occurred. * @param file: pointer to the source file name * @param line: assert_param error line source number * @retval None */ void assert_failed(uint8_t *file, uint32_t line) { /* USER CODE BEGIN 6 */ /* User can add his own implementation to report the file name and line number, ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */ /* USER CODE END 6 */ } #endif /* USE_FULL_ASSERT */

以上为需要添加代码的配置