前几天刚刚参加完第十四届的省赛，这届题目比我想象中的要难，其实想一想这也是应该的，以前的知识点都被摸透了，也是需要加入新的知识点了，但是我还是想说能不能别在我参加的时候加大题目难度啊。
不过听说隔壁单片机的省赛都比往年的国赛还难，这就有点离谱了。好了，进入正题了，老规矩先看看客观题。
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
提取码：np1p
有什么不理解的地方，可以在评论区提出来嗷。
这届题目用到的模块是LCD，LED，按键，ADC，PWM和脉冲捕获。其中新考点就是按键的长按和脉冲输入捕获。
按键长按的话，由于我是在定时器中每10ms扫描一次按键，按照题目要求长按时间是2s以上，所以设置一个变量用来计数，如果在按键松开时计数值达到200以上就是长按，否则就是短按。
脉冲捕获，其实就是使用定时器获得一个方波周期的时间，再用定时器频率 / 时间t就可以计算出引脚的输出频率了。
如图所示，当有上升沿发生就进入中断，开始计时，当下一个上升沿来到时也进入中断，这就可以获得时间t计算出频率，然后再清除t的值，具体看代码。再多使用一个通道捕获下降沿的时间t1，就可以计算出占空比，用高电平的时间t1 / 总的时间t。感兴趣的可以试试，多准备准备，以防下次会考。说完了，那就配置CubeMX吧。
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，PB15设置为ADC2的15通道，PA1设置为定时器2的第2通道，PA7设置为定时器17的通道1，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。
设置定时器3每10ms中断一次。
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。
开启定时器中断，设置通道1为上升沿的输入捕获。
勾选ADC2的第15通道，其他设置默认就行。
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。
main.c
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file : main.c
* @brief : Main program body
******************************************************************************
* @attention
*
* <h2><center>© Copyright (c) 2023 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 "adc.h"
#include "tim.h"
#include "gpio.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "sys.h"
#include "show.h"
#include "lcd.h"
#include "timer.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 btn,long_btn; //按键短按值，和key4的长按标志
extern uint32_t f; //是捕获计算的频率
bool choice = 0; //0是参数R，1是参数K
bool fre_flag = 0; //切换高低频模式的锁，为1时不能切换
bool lock = 0; //为1时占空比锁定
char M='L'; //L是低频模式，H是高频模式
uint8_t jm = 0; //0是数据界面，1是参数界面，2记录界面
uint16_t P = 100; //占空比
uint8_t N = 0;
uint8_t R = 1,K = 1;
uint8_t tempR = 1,tempK = 1;
float V = 0.0f,MH = 0.0f,ML = 0.0f;
float Volt = 0.0f;
/* 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_ADC2_Init();
MX_TIM2_Init();
MX_TIM3_Init();
MX_TIM17_Init();
/* USER CODE BEGIN 2 */
LCD_Init();
LCD_Clear(Black);
LCD_SetBackColor(Black);
LCD_SetTextColor(White);
HAL_TIM_Base_Start_IT(&htim3);
HAL_TIM_PWM_Start(&htim2,TIM_CHANNEL_2);
HAL_TIM_IC_Start_IT(&htim17,TIM_CHANNEL_1);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
Volt = getADC(&hadc2);
V = (f*2*R*3.14f)/(100*K);
switch(btn)
{
case 1:
{
Key1();
btn = 0;
}
break;
case 2:
{
Key2();
btn = 0;
}
break;
case 3:
{
Key3();
btn = 0;
}
break;
case 4:
{
Key4();
btn = 0;
}
break;
}
if(long_btn && 0 == jm)
{
lock = 1;
long_btn = 0;
}
if(0==jm)
DATA();
else if(1==jm)
PARA();
else
RECD();
LED_Hint(); //处理LED
InferDuty(); //调整占空比
InferFre(); //计算最大最小速度值
}
/* 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_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();
}
/** Initializes the peripherals clocks
*/
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_ADC12;
PeriphClkInit.Adc12ClockSelection = RCC_ADC12CLKSOURCE_SYSCLK;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != 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 */
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
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 <string.h>
#include <stdbool.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 */
/* USER CODE END Private defines */
#ifdef __cplusplus
}
#endif
#endif /* __MAIN_H */
main.h中添加了几个头文件和define。
sys.c
#include "sys.h"
Btn key[4] = {0};
uint8_t btn = 0, long_btn = 0;
uint16_t LED = 0xff00;
extern uint8_t jm;
extern bool L2_flag;
extern bool fre_flag;
extern bool lock, choice;
extern uint8_t R ,K ,N;
extern uint8_t tempR ,tempK;
void LED_SET(void)
{
GPIOC->ODR = (uint32_t)LED;
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(0 == jm)
{
LED &= ~(0x01ff);
LED_SET();
}
else
{
LED |= 0x0100;
LED_SET();
}
if(1 == L2_flag && 1 == fre_flag)
{
LED &= ~(0x02ff);
LED_SET();
}
else
{
LED |= 0x0200;
LED_SET();
}
if(1 == lock)
{
LED &= ~(0x04ff);
LED_SET();
}
else
{
LED |= 0x0400;
LED_SET();
}
}
void KEY_Scan(void)
{
uint8_t i;
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;
if(3 == i)
key[i].long_time = 1;
}
else
key[i].state = 0;
}
break;
case 2:
{
if(key[i].press == 1)
{
key[i].state = 0;
if(key[3].long_time>=200)
long_btn = i+1;
else
key[3].long_time++;
}
if(3 == i)
key[3].long_time++;
}
break;
}
}
}
float getADC(ADC_HandleTypeDef *pin)
{
uint16_t adc;
HAL_ADC_Start(pin);
adc = HAL_ADC_GetValue(pin);
return adc*3.3/4096;
}
void Key1(void) //按键1需要完成的功能
{
if(3 == ++jm)
jm = 0;
if(1 == jm)
{
tempR = R;
tempK = K;
}
else // 从参数界面退出时，新的 R 参数和 K 参数生效。
{
R = tempR;
K = tempK;
}
choice = 0;
LCD_Clear(Black);
}
void Key2(void) //按键2需要完成的功能
{
if(0 == jm && 0 == fre_flag)
{
fre_flag = 1;
N++;
}
if(1 == jm)
{
choice ^= 1;
}
}
void Key3(void) //按键3需要完成的功能
{
if(1 == jm)
{
if(0 == choice)
{
if(++tempR>10)
tempR = 1;
}
else
{
if(++tempK>10)
tempK = 1;
}
}
}
void Key4(void) //按键4需要完成的功能
{
if(1 == jm)
{
if(0 == choice)
{
if(--tempR<1)
tempR = 10;
}
else
{
if(--tempK<1)
tempK = 10;
}
}
if(0 == jm)
lock = 0;
}
sys.h
#ifndef __SYS_H
#define __SYS_H
#include "main.h"
#include "lcd.h"
typedef struct{
bool press;
uint8_t state;
uint16_t long_time;
}Btn;
void LED_SET(void);
void LED_Hint(void);
void KEY_Scan(void);
float getADC(ADC_HandleTypeDef *pin);
void Key1(void);
void Key2(void);
void Key3(void);
void Key4(void);
#endif
led使用寄存器，目的是单独控制一个LED灯时不干扰其他LED灯，使用HAL库函数，改变一个灯的值，会干扰到其他灯的显示，有没有好心人在评论区告知一下怎么使用HAL库才不会有这种情况，感谢。
show.c
#include "show.h"
char text[21] = {0};
extern uint8_t N,R,K;
extern uint16_t P;
extern uint16_t fre;
extern float V,MH,ML;
extern char M;
extern float Volt;
extern bool lock;
extern uint8_t tempR,tempK;
void LCD_SHOW(uint8_t line, char *text)
{
LCD_DisplayStringLine(line*24, (u8 *)text);
}
void DATA(void)
{
sprintf(text," DATA ");
LCD_SHOW(1,text);
sprintf(text," M=%c ",M);
LCD_SHOW(3,text);
sprintf(text," P=%d%% ",P);
LCD_SHOW(4,text);
sprintf(text," V=%.1f ",V);
LCD_SHOW(5,text);
}
void PARA(void)
{
sprintf(text," PARA ");
LCD_SHOW(1,text);
sprintf(text," R=%d ",tempR);
LCD_SHOW(3,text);
sprintf(text," K=%d ",tempK);
LCD_SHOW(4,text);
}
void RECD(void)
{
sprintf(text," RECD ");
LCD_SHOW(1,text);
sprintf(text," N=%d ",N);
LCD_SHOW(3,text);
sprintf(text," MH=%.1f ",MH);
LCD_SHOW(4,text);
sprintf(text," ML=%.1f ",ML);
LCD_SHOW(5,text);
}
void InferDuty(void)//调整占空比
{
if(lock == 0)
{
if(Volt<=1.0f)
{
P = 10*(fre+1)/100;
__HAL_TIM_SET_COMPARE(&htim2,TIM_CHANNEL_2,P);
}
else if(Volt>=3.0f)
{
P = 85*(fre+1)/100;
__HAL_TIM_SET_COMPARE(&htim2,TIM_CHANNEL_2,P);
}
else
{
P = 37.5f*Volt-27.5f;
__HAL_TIM_SET_COMPARE(&htim2,TIM_CHANNEL_2,P*(fre+1)/100);
}
}
}
void InferFre(void)//计算最大最小速度值
{
ML = (4000*2*R*3.14f)/(100*K);
MH = (8000*2*R*3.14f)/(100*K);
}
show.h
#ifndef __SHOW_H
#define __SHOW_H
#include "main.h"
#include "lcd.h"
#include "tim.h"
void LCD_SHOW(uint8_t line, char *text);
void DATA(void);
void PARA(void);
void RECD(void);
void InferDuty(void);
void InferFre(void);
#endif
timer.c
#include "timer.h"
uint16_t CCR1 = 0;
uint32_t fre_CNT = 0;
uint16_t fre = 999;
uint32_t f = 0;
uint8_t L2_CNT = 0;
bool L2_flag = 0;
extern bool fre_flag;
extern char M;
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
if(htim->Instance == TIM3)
{
KEY_Scan();
if(1 == fre_flag) //高低频模式切换，5秒钟内保证占空比不变，频率每10ms加减一
{ //500次刚好完成高低频模式切换需要改变的自动重装载值
if(++fre_CNT>500)
{
fre_flag = 0;
fre_CNT = 0;
if('L' == M)
M = 'H';
else
M = 'L';
}
else
{
if('L' == M)
{
fre--;
__HAL_TIM_SET_AUTORELOAD(&htim2,fre);
}
else
{
fre++;
__HAL_TIM_SET_AUTORELOAD(&htim2,fre);
}
}
if(++L2_CNT>10)
{
L2_flag ^= 1;
L2_CNT = 0;
}
}
}
}
void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim)
{
/*PWM 信号上升沿时，会进入中断，IC1会捕获，对应的是周期宽度测量*/
if(htim->Instance == TIM17)
{
if(htim->Channel==HAL_TIM_ACTIVE_CHANNEL_1)
{
CCR1 = HAL_TIM_ReadCapturedValue(htim,TIM_CHANNEL_1);
__HAL_TIM_SetCounter(htim,0);
f = (80000000/80)/(CCR1+1);
HAL_TIM_IC_Start(htim,TIM_CHANNEL_1);
}
}
}
timer.h
#ifndef __TIMER_H
#define __TIMER_H
#include "main.h"
#include "tim.h"
#include "sys.h"
#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十四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。