蓝桥杯嵌入式第十三届省赛题目解析
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：
收集的一些历年的比赛客观题和解析，以及程序设计题的PDF，在这里分享给大家。
链接：https://pan.baidu.com/s/1hTw0inSbLjX57hOtankgKw
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
时钟配置完了，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的版本。
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LCD
LCD_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3
HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_2); //初始化PWM
HAL_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
else
if(++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;
else
if(++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;
else
if(++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();
else
STA();
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
#include
#include
/* 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);
else
LED_Show(0xFD, GPIO_PIN_SET);
if(L2 == 1)
LED_Show(0x02, GPIO_PIN_RESET);
else
LED_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;
}
else
key[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。