蓝桥杯嵌入式第8届真题(完成) STM32G431

题目

分析和代码

对比第六届和第七届，这届的题目在逻辑思维上确实要麻烦不少，可以从题目看出，这届题目对时间顺序的要求很严格，所以就可以使用状态机的思想来编程，拿到类似题目不要急着写代码，一定要先分析好步骤，想出状态转换的逻辑后，在根据逻辑写代码写起来就很快了。

main.c

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2021 STMicroelectronics.
  * All rights reserved.</center></h2>
  *
  * This software component is licensed by ST under BSD 3-Clause license,
  * the "License"; You may not use this file except in compliance with the
  * License. You may obtain a copy of the License at:
  *                        opensource.org/licenses/BSD-3-Clause
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "rtc.h"
#include "tim.h"
#include "gpio.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "key.h"
#include "led.h"
#include "string.h"
#include "stdio.h"
/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
extern struct Key key[4];//4个按键
uint8_t lcdtext[30]; //lcd显示的内容
uint8_t status[30]; //lcd显示的内容
uint8_t led;//LED状态
uint8_t setfloor[5]={0,0,0,0,0};//四层楼，为了方便1-4所以数组大小为5
uint32_t key_time_1s; //按键按下后等待的1s
uint32_t open_or_close_door_time_4s; //开门或者关门所需时间
uint32_t up_or_down_dir_time_6s; //电梯往上一楼或者往下一楼所需的时间
uint32_t wait_time_2s; //电梯在每层楼等待时间
uint8_t current_floor = 1;//当前所在层
RTC_DateTypeDef D; //用于显示日期
RTC_TimeTypeDef T; //用于显示时间
uint8_t process_status = 0;//执行的状态
uint8_t dir = 2;//是上还是下，默认停止
//下面用于流水灯的部分
uint32_t lastUpdateTime = 0; // 上次更新LED状态的时间
const uint32_t updateInterval = 200; // 更新间隔，以毫秒为单位
uint8_t flow_led_enable = 0;  //是否打开流水灯
/* 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 */
void led_process(void);
void key_process(void);
void lcd_process(void);
void status_process(void);

/* 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();
  MX_RTC_Init();
  MX_TIM16_Init();
  MX_TIM17_Init();
  /* USER CODE BEGIN 2 */
		HAL_TIM_Base_Start_IT(&htim2);
    LCD_Init();
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */

    LCD_Clear(Black);
    LCD_SetBackColor(Black);
    LCD_SetTextColor(White);
		LED_display(0x00);
		sprintf((char *)lcdtext,"        %d",current_floor); //默认为1楼
		LCD_DisplayStringLine(Line3,lcdtext);
    

    while (1)
    {
			led_process();
			lcd_process();
			key_process();
			status_process();
    /* USER CODE END WHILE */

    /* 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};
  RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};

  /** Configure the main internal regulator output voltage
  */
  HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1);
  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI|RCC_OSCILLATORTYPE_LSI;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.LSIState = RCC_LSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
  RCC_OscInitStruct.PLL.PLLM = RCC_PLLM_DIV2;
  RCC_OscInitStruct.PLL.PLLN = 20;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;
  RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;
  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_DIV1;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
  /** Initializes the peripherals clocks
  */
  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_RTC;
  PeriphClkInit.RTCClockSelection = RCC_RTCCLKSOURCE_LSI;

  if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
  {
    Error_Handler();
  }
}

/* USER CODE BEGIN 4 */
void key_process(void)
{
	
	if((process_status==0||process_status==1))//没有按键按下时，和按键按下1s内还可以继续按
	{
		sprintf((char *)status,"    wait key      ");
		if(key[0].key_flag&&current_floor!=0+1) //不能是当前楼层
		{
			key[0].key_flag = 0;
			setfloor[1] = 1;//设置目标楼层
			led|=0x01; //设置对应led打开
			
			LED_display(led);//打开对应led
			process_status = 1;//按键按下后进入1s等待状态
			key_time_1s = uwTick; //更新按键按下时时间
		}
		if(key[1].key_flag&&current_floor!=1+1)
		{
			key[1].key_flag = 0;
			setfloor[2] = 1;
			led|=0x02;
			LED_display(led);
			process_status = 1;
			key_time_1s = uwTick;
		}
		if(key[2].key_flag&&current_floor!=2+1)
		{
			key[2].key_flag = 0;
			setfloor[3] = 1;
			led|=0x04;
			LED_display(led);
			process_status = 1;
			key_time_1s = uwTick;
		}
		if(key[3].key_flag&&current_floor!=3+1)
		{
			key[3].key_flag = 0;
			setfloor[4] = 1;
			led|=0x08;
			LED_display(led);
			process_status = 1;
			key_time_1s = uwTick;
		}
		
	
	}
	

}

void lcd_process(void)
{
	HAL_RTC_GetDate(&hrtc,&D,RTC_FORMAT_BIN);
	HAL_RTC_GetTime(&hrtc,&T,RTC_FORMAT_BIN);
	sprintf((char *)lcdtext,"      FLOOR");
	LCD_DisplayStringLine(Line1,lcdtext);
//	sprintf((char *)lcdtext,"        %d",current_floor);
//	LCD_DisplayStringLine(Line3,lcdtext);
	sprintf((char *)lcdtext,"     %02d:%02d:%02d",T.Hours,T.Minutes,T.Seconds);
	LCD_DisplayStringLine(Line4,lcdtext);
	//LCD_ClearLine(Line7);
	sprintf((char *)lcdtext,"%s",status);
	LCD_DisplayStringLine(Line7,lcdtext);
	sprintf((char *)lcdtext,"  floors:%d-%d-%d-%d",setfloor[1],setfloor[2],setfloor[3],setfloor[4]);
	LCD_DisplayStringLine(Line8,lcdtext);
}

void status_process(void)
{
	if(process_status)
	{
		switch(process_status)
		{
			case 1: //状态1：等待1s内是否有按键按下
			{
			
				sprintf((char *)status,"      wait key 1s    ");
				if((uwTick-key_time_1s)>=1000) //如果1s到了，进入下一个关门状态
				{
				
					sprintf((char *)status,"  key_1s_yes     ");
					process_status = 2;
				}
			}break;
			case 2: //状态2：开始关门
			{
			
				sprintf((char *)status,"  close door     ");
				HAL_GPIO_WritePin(GPIOA,GPIO_PIN_5,GPIO_PIN_RESET);//关门
				__HAL_TIM_SET_COMPARE(&htim17,TIM_CHANNEL_1,250); //占空比50%
				HAL_TIM_PWM_Start(&htim17,TIM_CHANNEL_1);
				process_status = 3; //进入等待关门状态
				open_or_close_door_time_4s = uwTick;//更新关门时间
			}break;
			case 3://状态3：4s关门时间等待，关完门开始判断电梯是上行还是下行
			{
		
				sprintf((char *)status,"wait close door 4s    ");
				if(uwTick-open_or_close_door_time_4s>=4000) //关门后，开始判断上下行
				{
					
					sprintf((char *)status,"close door yes     ");
					int up = 0, down = 0;
					HAL_TIM_PWM_Stop(&htim17,TIM_CHANNEL_1);
					// 检查上行
					for(int i = current_floor + 1; i < 5; i++) { //如果电梯数组中存在比当前楼层高的楼层被设置
							if(setfloor[i] == 1) {
									up = 1;
									break;
							}
					}
    
					// 检查下行
					for(int i = current_floor - 1; i >= 1; i--) { //如果电梯数组中存在比当前楼层低的楼层被设置
							if(setfloor[i] == 1) {
									down = 1;
									break;
							}
					}
						// 判断方向
					if(up && !down) { //只有往上
							dir = 1;
					} else if(down && !up) { //只有往下
							dir = 0;
					} else if(up && down) { //上下都有，先向上
							dir = 1;
					} else {
							dir = 2; //都没有
					}
					
					sprintf((char *)status,"   move          ");
					sprintf((char *)lcdtext,"    dir:%d--%d",up,down);
					LCD_DisplayStringLine(Line9,lcdtext);
					if(dir==1)//上行
					{
						flow_led_enable = 1;
						HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_SET);
						__HAL_TIM_SET_COMPARE(&htim16,TIM_CHANNEL_1,800); //占空比80%
						HAL_TIM_PWM_Start(&htim16,TIM_CHANNEL_1);
						up_or_down_dir_time_6s = uwTick;//更新上行时间
						process_status = 4;
					}else if(dir==0)//下行
					{
						flow_led_enable = 1;
						HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_RESET);
						__HAL_TIM_SET_COMPARE(&htim16,TIM_CHANNEL_1,600); //占空比80%
						HAL_TIM_PWM_Start(&htim16,TIM_CHANNEL_1);
						up_or_down_dir_time_6s = uwTick;//更新上行时间
						process_status = 4;
					}else if(dir==2)//既不需要上行也不需要下行，回到电梯状态
					{
						process_status = 0;
					}
					
				}
			}break;
			case 4://状态4：等待6s上下行时间
			{
				
				sprintf((char *)status," wait move 6s        ");
				if(uwTick-up_or_down_dir_time_6s>=6000) //上下行时间到了
				{
			
					sprintf((char *)status," move yes       ");
					if(dir==1) //如果是上行
					{
						current_floor+=1;
	
					}
					else{
						current_floor-=1;
					}
					HAL_TIM_PWM_Stop(&htim16,TIM_CHANNEL_1);//
					setfloor[current_floor] = 0;//已到达该层
				// 显示楼层号并闪烁两次
					for(int i = 0; i < 2; i++) // 闪烁两次
					{
							sprintf((char *)lcdtext,"        %d",current_floor);
							LCD_DisplayStringLine(Line3, lcdtext); // 显示楼层号
							HAL_Delay(500); // 延时500ms
							LCD_ClearLine(Line3); // 清除楼层号显示
							HAL_Delay(500); // 延时500ms
					}
					// 再次显示楼层号
					sprintf((char *)lcdtext,"        %d",current_floor);
					LCD_DisplayStringLine(Line3, lcdtext);
					switch(current_floor)
        {
            case 1:
            {
                led &= ~0x01; // 使用位清除操作关闭LED1
            }break;
            case 2:
            {
                led &= ~0x02; // 关闭LED2
            }break;
            case 3:
            {
                led &= ~0x04; // 关闭LED3
            }break;
            case 4:
            {
                led &= ~0x08; // 关闭LED4
            }break;
        }
        LED_display(led); // 更新LED显示
				flow_led_enable = 0; // 关闭流水灯
        led &= 0x0F; // 保持低四位状态不变，关闭高四位LED
        LED_display(led); // 更新LED显示
				open_or_close_door_time_4s = uwTick;//更新开门时间
					process_status =5;
				}
			}break;
				case 5 ://状态5:等待开门4s时间到
			{
				
				sprintf((char *)status," wait open door 4s       ");
				if(uwTick-open_or_close_door_time_4s>=4000)//打开门
				{
					
					sprintf((char *)status," open door yes     ");
					wait_time_2s = uwTick;//更新等待时间
					process_status = 6;
				}
			}break;
			case 6 ://状态5:等待开门4s时间到
			{
				
				sprintf((char *)status," wait  2s       ");
				if(uwTick-wait_time_2s>=2000)//每层停留时间
				{
					
					sprintf((char *)status," wait  2s yes     ");
					wait_time_2s = uwTick;//更新等待时间
					process_status = 2;
				}
			}break;
			
		}
	
	}
	
}

void led_process(void)
{
    static uint8_t flow_led_state = 0; // 初始状态为0，表示流水灯未激活

    if((uwTick - lastUpdateTime) >= updateInterval && flow_led_enable)
    {
        lastUpdateTime = uwTick; // 更新最后一次更新时间

        if(flow_led_state == 0) // 如果流水灯未激活，根据方向初始化流水灯状态
        {
            flow_led_state = (dir == 1) ? 0x08 : 0x01; // 从左侧或右侧开始
        }
        else
        {
            if(dir == 1) // 上行：从右到左流水
            {
                flow_led_state <<= 1; // 向左移动
                if(flow_led_state > 0x08) // 如果超过了最左侧，重置到最右侧
                {
                    flow_led_state = 0x01;
                }
            }
            else if(dir == 0) // 下行：从左到右流水
            {
                flow_led_state >>= 1; // 向右移动
                if(flow_led_state < 0x01) // 如果超过了最右侧，重置到最左侧
                {
                    flow_led_state = 0x08;
                }
            }
        }

        // 更新LED状态，仅修改高四位，保持低四位不变
        // 注意：这里假设flow_led_state只影响一个LED，需要根据实际情况调整
        led = (led & 0x0F) | (flow_led_state << 4); // 将流水灯状态左移4位，合并到led的高四位
        LED_display(led); // 更新LED显示
    }
}



/* 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 */

  /* 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,
       tex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

key.c

#include "key.h"

struct Key key[4] = {0,0,0,0};

extern uint8_t process_status;
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
	if(htim->Instance==TIM2)
	{
		if((process_status==0||process_status==1))
		{
				key[0].key_gpio = HAL_GPIO_ReadPin(GPIOB,GPIO_PIN_0);
				key[1].key_gpio = HAL_GPIO_ReadPin(GPIOB,GPIO_PIN_1);
				key[2].key_gpio = HAL_GPIO_ReadPin(GPIOB,GPIO_PIN_2);
				key[3].key_gpio = HAL_GPIO_ReadPin(GPIOA,GPIO_PIN_0);
				for(int i = 0;i<4;i++)
				{
					switch(key[i].key_index)
					{
						case 0:
						{
							if(key[i].key_gpio==0)
							{
								key[i].key_index=1;
							}
						}break;
						case 1:
						{
							if(key[i].key_gpio==0)
							{
								key[i].key_flag =1;
								key[i].key_index=2;
							}else{
								key[i].key_index=0;
							}
						}break;
						case 2:
						{
							if(key[i].key_gpio==1)
							{
								key[i].key_index=0;
							
							}
						}break;
					}
		
			}
		}
	}
	
}

我一共将这个题目分为了6个状态

1. 状态0

此状态用于等待按键按下以设置目标楼层，只要右按键按下，就将对应的楼层数组置1，打开对应的led，记录当前按键按下的时间，最后进入状态1

2. 状态1：

此状态的进入是由于存在按键被按下，设置了目标楼层，该状态一直等待1s的到来，在状态0和状态1状态下按键仍然可以按下，因为某个按键按下后，在1s内仍然可以设置目标楼层，每一次重新按下按键，倒计时都会刷新，同样为了防止其余状态下按键仍然可以按下导致flag置1，在key.c的定时器回调函数中也只有状态0和状态1才能判断按键是否按下

3. 状态2：

此状态为开始关门状态，根据题目要求，将PA5置低电平，同时设置TIM17通道1的占空比为50% ，更新关门时间，进入状态3

4. 状态3：

题目要求开关门都需要4s，所以此状态为等待关门状态，等待结束后，开始根据setfloor数组确定当前电梯是向上，还是向下，设置的楼层会导致4种状态

• 只有比当前楼层高的楼层被设置，dir=1,往上走
• 只有比当前楼层低的楼层被设置，dir=0，往下走
• 比当前楼层高的和低的都设置，例如当前楼层是2层，比2层低的1层和比2层高的3，4层都被设置，dir=1,同样先向上走，再往下走
• 默认状态都没有被设置，在按键时已经限制条件不能设置当前楼层，dir=2，保持在当前楼层

根据dir的取值，设置上行还是下行，并打开对应PWM输出和电平信号，更新电梯开始上下行时间，或者是就在当前层然后，回到状态0，等待设置目标楼层

5. 状态4：

题目要求上行或者下行都需要6s，该状态是为了等待6s到来，时间到来后，根据dir将当前楼层+1或者-1，同时当前楼层闪烁两次，关闭当前楼层对应的led灯，关闭流水灯，然后更新开始开门时间，进入状态5

6. 状态5:

等待开门时间4s，时间到达后，更新每层停留的2s时间，进入下一个状态，状态6

7. 状态6:

每层的等待时间2s，等待完后回到，状态2开始关门，继续按顺序执行，直到没有目标楼层，回到状态0等待按键按下。

led.c

#include "led.h"

void LED_display(uint8_t led)
{
	HAL_GPIO_WritePin(GPIOC,GPIO_PIN_All,GPIO_PIN_SET);
	HAL_GPIO_WritePin(GPIOD,GPIO_PIN_2,GPIO_PIN_SET);
	HAL_GPIO_WritePin(GPIOD,GPIO_PIN_2,GPIO_PIN_RESET);
	HAL_GPIO_WritePin(GPIOC,led<<8,GPIO_PIN_RESET);
	HAL_GPIO_WritePin(GPIOD,GPIO_PIN_2,GPIO_PIN_SET);
	HAL_GPIO_WritePin(GPIOD,GPIO_PIN_2,GPIO_PIN_RESET);
}

led_process用于处理流水灯，根据电梯运行方向确定，流水灯方向，led = (led & 0x0F) | (flow_led_state << 4); 这句的意思是首先保持低四位的保持不变，然后将流水灯的状态左移4位，与之相或从而实现不影响低四位led的效果

为了便于观察状态，添加了一些表示状态的信息显示在lcd上，时间控制大部分使用滴答定时器uwTick以防止delay阻塞程序