马上就要比赛了，我也是把自己写完调试好的题目分享出来给大家，同时也祝大家取得自己理想的成绩。 好了废话不多说，我们先看客观题再看程序设计题。

目录

客观题： 

程序设计题：

题目解析：

CubeMX配置

代码演示：

---

客观题： 

第十三届的客观题考察的是比较基础的知识的了，其中第一题和最后一题都可以在参考手册（比赛时允许查阅）中找到不需要死记。本次客观题的解析来自4梯，里面还有客观题的视频讲解哦。

程序设计题：

题目解析：

 十三届的程序设计题用到了LCD，LED，按键，串口和PWM，都是老朋友了。

其中PWM主要用到了两个函数，一个用来改变PWM的频率，一个用来改变PWM的占空比。

//通过修改PWM的自动重装载值（ARR）来修改PWM的频率

__HAL_TIM_SET_AUTORELOAD(&htim2,499); 

//修改PWM的占空比（CCRX）
__HAL_TIM_SET_COMPARE(&htim2,TIM_CHANNEL_2,50);

注意：PWM的占空比 = CCRX / （ARR+1），例如以上代码就是设置定时器2的第二通道的ARR为499，CCRX为50，所以占空比为50/(499+1) = 10%

而串口主要是处理接收的字符串，就可以使用sscanf()函数来切割字符串。

函数原型：int sscanf(const char *str, const char *format, ...)

详细用法感兴趣的可以百度一下，简单说一下这个函数的用法是从字符串读取格式化输入，其实和scanf()用法差不多，举个例子吧 sscanf(rxarr, "%d-%d",&Old_PWD,&New_PWD);

以上用法是，从串口接收的字符串rxarr假如是"123-789"，那么就把“123”转化成整数型赋值给Old_PWD，把“789”转化成整数型赋值给New_PWD

说完了就从 CubeMX配置开始吧。

CubeMX配置

 

 

 始终配置完了，需要按下回车（Enter）来保存。

 根据原理图配置GPIO引脚，其中lcd和led的引脚都设置为output，按键设置为input，串口使用USART1也就是PA10和PA9，PWM是PA1设置为定时器2的第二通道，需要把PD2也设置为output用来作为led的锁存器。

 在GPIO中选中按键的引脚，设置为上拉输入模式。

 在GPIO中，选中led的引脚，设置为初始状态为高电平，推挽输出模式，既不上拉也不下拉。其他引脚使用默认设置就是行。

需要把定时器2的通道2设置为PWM通道2，然后设置预分频器值和自动重装值以及占空比。

 

设置定时器3每10ms中断一次。

 设置串口1的波特率为9600，开启中断，其他默认即可。

设置项目名字和保存路径（建议不要有中文），以及IDE的板本。 

 勾选这个主要是让.c和.h文件单独分开，之后就可以生成代码了，CubeMX配置就完成了，如果之后想要添加新的模块或者修改配置好了模块的值，可以直接在文件中打开CubeMX的工程进行修改，改完后再点击GENERATE CODE就行了。

代码演示：

main.c

/* USER CODE BEGIN Header */
/********************************************************************************* @file           : main.c* @brief          : Main program body******************************************************************************* @attention** Copyright (c) 2023 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 "usart.h"
#include "gpio.h"/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "led.h"
#include "timer.h"
#include "display.h"
#include "lcd.h"
/* 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 */
extern uint8_t rxdata;   //串口接收的单个字符
extern uchar btn;        //按键值
extern uchar STA_Flag;   //密码正确的标志
char text[21];           //输出到LCD的字符串
uint PWD = 123;          //密码值
char B1 = '@',B2 = '@',B3 = '@';
bool jm = 0;             //0表示密码输入界面，1表示输出状态界面
uchar CNT = 0;           //密码输入错误的计数值
bool L1 = 0,L2 = 0,L2_Flag = 0;   //L1是LED1标志位，L2是LED2的标志位，L2_flag是LED2 5秒计时的标志位
/* 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();MX_TIM3_Init();MX_USART1_UART_Init();/* USER CODE BEGIN 2 */LED_Show(0xFF,GPIO_PIN_SET);                //初始化LED，使其全灭LCD_Init();                                 //初始化LCDLCD_Clear(Black);                           //清屏为黑色LCD_SetBackColor(Black);                    LCD_SetTextColor(White);HAL_TIM_Base_Start_IT(&htim3);              //初始化定时器3HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_2);    //初始化PWMHAL_UART_Receive_IT(&huart1, &rxdata, 1);     //初始化串口接收/* USER CODE END 2 *//* Infinite loop *//* USER CODE BEGIN WHILE */while (1){/* USER CODE END WHILE *//* USER CODE BEGIN 3 */switch(btn){case 1:             //按键1使密码的第一位从@-0-9-0{if(jm == 0){if(B1 == '@')B1 = 48; //字符'0'的ASCII值elseif(++B1>=58)B1 = 48;}btn = 0;}	break;case 2:            //按键2使密码的第二位从@-0-9-0{if(jm == 0){if(B2 == '@')B2 = 48;elseif(++B2>=58)B2 = 48;}btn = 0;}break;case 3:            //按键3使密码的第三位从@-0-9-0{if(jm == 0){if(B3 == '@')B3 = 48;elseif(++B3>=58)B3 = 48;}btn = 0;}break;case 4:             //按键4，处理密码是否正确{if(jm == 0){if(PWD == (B1-48)*100+(B2-48)*10+(B3-48)){jm = 1;	LCD_Clear(Black);__HAL_TIM_SET_AUTORELOAD(&htim2,499);__HAL_TIM_SET_COMPARE(&htim2,TIM_CHANNEL_2,50);L1 = 1;STA_Flag = 1;}else{if(++CNT>=3){L2_Flag = 1;CNT = 0;}B1 = '@',B2 = '@',B3 = '@';}}btn = 0;}break;}if(STA_Flag == 2)      //密码正确进入输出状态界面{STA_Flag = 0;jm = 0;LCD_Clear(Black);__HAL_TIM_SET_AUTORELOAD(&htim2,999);__HAL_TIM_SET_COMPARE(&htim2,TIM_CHANNEL_2,500);B1 = '@',B2 = '@',B3 = '@';}if(jm == 0)PSD();elseSTA();LED_Hint();           //LED的处理UART_RX();            //串口接收处理函数}/* USER CODE END 3 */
}/*** @brief System Clock Configuration* @retval None*/
void SystemClock_Config(void)
{RCC_OscInitTypeDef RCC_OscInitStruct = {0};RCC_ClkInitTypeDef RCC_ClkInitStruct = {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_HSE;RCC_OscInitStruct.HSEState = RCC_HSE_ON;RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;RCC_OscInitStruct.PLL.PLLM = RCC_PLLM_DIV3;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();}
}/* 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 */

main.h

/* USER CODE BEGIN Header */
/********************************************************************************* @file           : main.h* @brief          : Header for main.c file.*                   This file contains the common defines of the application.******************************************************************************* @attention** Copyright (c) 2023 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 *//* Define to prevent recursive inclusion -------------------------------------*/
#ifndef __MAIN_H
#define __MAIN_H#ifdef __cplusplus
extern "C" {
#endif/* Includes ------------------------------------------------------------------*/
#include "stm32g4xx_hal.h"/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include <stdio.h>
#include <stdbool.h>
#include <string.h>
/* USER CODE END Includes *//* Exported types ------------------------------------------------------------*/
/* USER CODE BEGIN ET *//* USER CODE END ET *//* Exported constants --------------------------------------------------------*/
/* USER CODE BEGIN EC *//* USER CODE END EC *//* Exported macro ------------------------------------------------------------*/
/* USER CODE BEGIN EM *//* USER CODE END EM *//* Exported functions prototypes ---------------------------------------------*/
void Error_Handler(void);/* USER CODE BEGIN EFP *//* USER CODE END EFP *//* Private defines -----------------------------------------------------------*/
/* USER CODE BEGIN Private defines */
#define uchar unsigned char
#define uint unsigned int
/* USER CODE END Private defines */#ifdef __cplusplus
}
#endif#endif /* __MAIN_H */

main.h中添加了几个头文件和define。

led.c

#include "led.h"extern bool L1;
extern bool L2;void LED_Show(uint16_t value,GPIO_PinState PinState)
{HAL_GPIO_WritePin(GPIOC,GPIO_PIN_All,GPIO_PIN_SET);HAL_GPIO_WritePin(GPIOC,value<<8,PinState);HAL_GPIO_WritePin(GPIOD,GPIO_PIN_2,GPIO_PIN_SET);HAL_GPIO_WritePin(GPIOD,GPIO_PIN_2,GPIO_PIN_RESET);
}void LED_Hint(void)
{if(L1 == 1)LED_Show(0x01, GPIO_PIN_RESET);elseLED_Show(0xFD, GPIO_PIN_SET);if(L2 == 1)LED_Show(0x02, GPIO_PIN_RESET);elseLED_Show(0xFE, GPIO_PIN_SET);
}

led.h

#ifndef __LED_H
#define __LED_H#include "main.h"void LED_Show(uint16_t value,GPIO_PinState PinState);
void LED_Hint(void);#endif

timer.c

#include "timer.h"Btn key[4];     //按键的数组，保存每个按键的状态
uchar btn = 0;  //返回给主函数是哪个按键按下
char rxarr[8];
uchar arrow = 0;
uint8_t rxdata;
uint STA_CNT = 0;
uint L1_CNT = 0,L2_Flag_CNT = 0;
uchar L2_CNT = 0;
volatile uchar STA_Flag = 0;extern bool L1,L2,L2_Flag;void KEY_Scan(void)      //按键扫描
{uchar i=0;key[0].press = HAL_GPIO_ReadPin(GPIOB,GPIO_PIN_0);key[1].press = HAL_GPIO_ReadPin(GPIOB,GPIO_PIN_1);key[2].press = HAL_GPIO_ReadPin(GPIOB,GPIO_PIN_2);key[3].press = HAL_GPIO_ReadPin(GPIOA,GPIO_PIN_0);for(i=0;i<4;i++){switch(key[i].state){case 0:if(key[i].press == 0)key[i].state = 1;break;case 1:if(key[i].press == 0){key[i].state = 2;btn = i+1;}elsekey[i].state = 0;break;case 2:if(key[i].press == 1)key[i].state = 0;break;}}
}void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)      //定时器3的中断回调函数
{if(htim->Instance == TIM3){KEY_Scan();if(STA_Flag == 1)      //状态输出界面计时5秒{if(++STA_CNT>=500){STA_Flag = 2;STA_CNT = 0;}}if(L1 == 1)           //LED1计时5秒{if(++L1_CNT>=500){L1_CNT = 0;L1 = 0;}}if(L2_Flag == 1)      //LED2闪烁计时5秒{if(++L2_CNT>=10){L2 ^= 1;L2_CNT = 0;}if(++L2_Flag_CNT>=500){L2_Flag = 0;L2_Flag_CNT = 0;L2 = 0;}}}
}void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)      //串口接收中断回调函数
{if(huart->Instance == USART1){rxarr[arrow++] = rxdata;HAL_UART_Receive_IT(&huart1, &rxdata, 1);}
}void UART_RX(void)         //判断串口有没有接收完字符
{uchar temp;if(arrow != 0){temp = arrow;HAL_Delay(1);if(temp == arrow)CH_Handle();}
}

timer.h

#ifndef __TIMER_H
#define __TIMER_H#include "main.h"
#include "usart.h"
#include "display.h"typedef struct 
{bool press;uchar state;
}Btn;void KEY_Scan(void);
void UART_RX(void);#endif

display.c

#include "display.h"extern char text[21];
extern uchar arrow;
extern char rxarr[8];
extern uint PWD;
extern char B1,B2,B3;void LCD_Print(uchar line, char *text)  //重新封装一下LCD显示函数，可以不写
{LCD_DisplayStringLine((u8)line*24, (u8 *)text);
}void CH_Handle(void)                   //串口接收到字符串的处理函数
{if(arrow>0){if(arrow == 7){uint Old_PWD = 0,New_PWD = 0;sscanf(rxarr, "%d-%d",&Old_PWD,&New_PWD);if(Old_PWD == PWD)PWD = New_PWD;}}arrow = 0;memset(rxarr,0,8);
}void PSD(void)      //密码显示界面
{sprintf(text,"       PSD          ");LCD_Print(0,text);sprintf(text,"    B1:%c            ",B1);LCD_Print(3,text);sprintf(text,"    B2:%c            ",B2);LCD_Print(4,text);sprintf(text,"    B3:%c            ",B3);LCD_Print(5,text);
}void STA(void)      //状态输出界面
{sprintf(text,"       STA          ");LCD_Print(0,text);sprintf(text,"    F:2000Hz        ");LCD_Print(3,text);sprintf(text,"    D:10%%           ");LCD_Print(4,text);
}

display.h

#ifndef __DISPLAY_H
#define __DISPLAY_H#include "main.h"
#include "LCD.h"
#include "usart.h"void LCD_Print(uchar line, char *text);
void CH_Handle(void);
void PSD(void);
void STA(void);#endif

以上就是我修改过的文件和新添加的文件。还有lcd模块，不过不需要我们自己写，官方有提供，直接复制过来就行，注意有三个文件，别只复制lcd.c和lcd.h。

 

 好了，以上就是蓝桥杯嵌入式第十三届省赛的题目解析了，如果有什么问题和建议都欢迎在评论区提出来喔。