【蓝桥杯嵌入式】13届程序题刷题记录及反思

一、题目分析

考察内容：

led
按键（短按）
PWM输出（PA1）
串口接收
lcd显示

根据PWM输出占空比调节，高频与低频切换

串口接收（指令解析）【中断接收】

2个显示界面

led灯闪烁定时器

二、Usr.c

/* Includes ------------------------------------------------------------------*/
#include "usr.h"
#include "usart.h"
/* values --------------------------------------------------------------------*/
struct keys key[4]={0,0,0,0};
uint8_t menu = 0;
uint8_t password_valid = 0;//密码有效信号
uint8_t password_err_3 = 0;//密码3次及以上输入错误信号
uint8_t password_err_time = 0;//密码3次及以上输入错误次数
uint8_t B1 = '@';
uint8_t B2 = '@';
uint8_t B3 = '@';
uint16_t F = 1000;
uint16_t D = 50;
uint16_t password = 123;//密码
/* define --------------------------------------------------------------------*/
#define MENU_PSD 0
#define MENU_STA 1/*----------------------------------------------------------------------------*/
void led_set(uint8_t led_dis)
{HAL_GPIO_WritePin(GPIOC,GPIO_PIN_All,GPIO_PIN_SET);//关闭所有ledHAL_GPIO_WritePin(GPIOC,led_dis<<8,GPIO_PIN_RESET);HAL_GPIO_WritePin(GPIOD,GPIO_PIN_2,GPIO_PIN_SET);HAL_GPIO_WritePin(GPIOD,GPIO_PIN_2,GPIO_PIN_RESET);
}
void led_2_toggle(void){HAL_GPIO_WritePin(GPIOC,GPIO_PIN_8,GPIO_PIN_SET);HAL_GPIO_WritePin(GPIOC,GPIO_PIN_10,GPIO_PIN_SET);HAL_GPIO_WritePin(GPIOC,GPIO_PIN_11,GPIO_PIN_SET);HAL_GPIO_WritePin(GPIOC,GPIO_PIN_12,GPIO_PIN_SET);HAL_GPIO_WritePin(GPIOC,GPIO_PIN_13,GPIO_PIN_SET);HAL_GPIO_WritePin(GPIOC,GPIO_PIN_14,GPIO_PIN_SET);HAL_GPIO_WritePin(GPIOC,GPIO_PIN_15,GPIO_PIN_SET);HAL_GPIO_TogglePin(GPIOC,GPIO_PIN_9);HAL_GPIO_WritePin(GPIOD,GPIO_PIN_2,GPIO_PIN_SET);HAL_GPIO_WritePin(GPIOD,GPIO_PIN_2,GPIO_PIN_RESET);
}//key_control
void key_control(void)
{if(key[0].single_flag == 1){key[0].single_flag = 0;//仅在PSD有效if(menu == MENU_PSD){if(B1 == '@'){B1 = '0';}else{B1++;if(B1>'9'){B1 = '0';}}}}else if(key[1].single_flag == 1){key[1].single_flag = 0;if(menu == MENU_PSD){if(B2 == '@'){B2 = '0';}else{B2++;if(B2>'9'){B2 = '0';}}}}else if(key[2].single_flag == 1){key[2].single_flag = 0;if(menu == MENU_PSD){if(B3 == '@'){B3 = '0';}else{B3++;if(B3>'9'){B3 = '0';}}}  }else if(key[3].single_flag == 1){       //密码输入完成确认key[3].single_flag = 0;//此处要写密码判断if((B1-'0')*100+(B2-'0')*10+(B3-'0') == password){password_valid = 1;}else{password_err_time ++;}if(password_valid == 1){menu = MENU_STA;password_err_3 = 0;password_err_time = 0;//输入成功将err次数清0}else{B1 ='@';B2 ='@';B3 ='@';if(password_err_time >= 3){password_err_3 = 1;}}}else{key[0].long_flag = 0;key[1].long_flag = 0;key[2].long_flag = 0;key[3].long_flag = 0;}
}
void dispaly_init(void){LCD_Clear(Black);LCD_SetBackColor(Black);LCD_SetTextColor(White);
}
void menu_display(void)
{char text[30]={NULL};if(menu == MENU_PSD){sprintf(text,"       PSD           ");LCD_DisplayStringLine(Line1,(u8*)text);sprintf(text,"    B1:%c     ",B1);LCD_DisplayStringLine(Line3,(u8*)text);sprintf(text,"    B2:%c     ",B2);LCD_DisplayStringLine(Line4,(u8*)text);sprintf(text,"    B3:%c     ",B3);LCD_DisplayStringLine(Line5,(u8*)text);}else{fre_2hz_duty_10_set();sprintf(text,"       STA           ");LCD_DisplayStringLine(Line1,(u8*)text);sprintf(text,"    F:%d",F);LCD_DisplayStringLine(Line3,(u8*)text);sprintf(text,"    D:%d",D);LCD_DisplayStringLine(Line4,(u8*)text);LCD_ClearLine(Line5);}
}//2hz
void fre_2hz_duty_10_set(void)
{F= 2000;D =10;__HAL_TIM_SetCompare(&htim2,TIM_CHANNEL_2,100-1);//占空比百分之10__HAL_TIM_SET_PRESCALER(&htim2,40-1);//2hz
}
//1hz 50%
void fre_1hz_duty_50_set(void){__HAL_TIM_SetCompare(&htim2,TIM_CHANNEL_2,500-1);//占空比百分之50__HAL_TIM_SET_PRESCALER(&htim2,80-1);//1hzF= 2000;D = 50;
}//定时器中断服务函数
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{if(htim->Instance == TIM6){key[0].key_sta = HAL_GPIO_ReadPin(B1_Port,B1_Pin);key[1].key_sta = HAL_GPIO_ReadPin(B2_Port,B2_Pin);key[2].key_sta = HAL_GPIO_ReadPin(B3_Port,B3_Pin);key[3].key_sta = HAL_GPIO_ReadPin(B4_Port,B4_Pin);for(uint8_t i =0;i<4;i++){switch(key[i].judge_sta){case 0:{if(key[i].key_sta == 0){key[i].judge_sta = 1;key[i].key_time = 0;}else {key[i].judge_sta = 0;}}break;case 1:{if(key[i].key_sta == 0){key[i].judge_sta = 2;}else{key[i].judge_sta = 0;}}break;case 2:{if(key[i].key_sta == 1){if(key[i].key_time< Short_time){key[i].single_flag = 1;key[i].judge_sta = 0;}}else{key[i].key_time++;if(key[i].key_time > Long_time){key[i].long_flag = 1;key[i].judge_sta = 0;}}}break;}}}if(htim->Instance == TIM7){static uint16_t time = 0;if(password_valid == 1){password_err_3 = 0;led_set(0x01);F= 2000;fre_2hz_duty_10_set();if(time>= 50-1){password_valid = 0;led_set(0x00);time = 0;menu = MENU_PSD;B1 = '@';B2 = '@';B3 = '@';}else{time ++;}}else if(password_err_3 == 1){static uint8_t cnt = 0;cnt ++;cnt %= 2;//led2翻转if(cnt == 0){led_set(0x02);}else{led_set(0x00);}//5s后接触报警if(time>= 50-1){password_err_3 = 0;led_set(0x00);time = 0;  //5s计时清零cnt = 0;}else{time ++;   //计时++}F= 1000;fre_1hz_duty_50_set();//方波1hz}else{time = 0;fre_1hz_duty_50_set();//方波1hz}                     }}//串口接收完成中断回调服务函数
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{if(huart->Instance == USART1){led_set(0xaa);if(((recevie[0]-'0')*100+(recevie[1]-'0')*10+(recevie[2]-'0') == password)&&(recevie[3]) == '-'){password = (recevie[4]-'0')*100+(recevie[5]-'0')*10+(recevie[6]-'0');}HAL_UART_Receive_IT(&huart1,recevie,7);}
}

三、Usr.h

#ifndef __USR_H__
#define __USR_H__#ifdef __cplusplus
extern "C" {
#endif/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "lcd.h"
#include "stdio.h"
#include "tim.h"
/* extern --------------------------------------------------------------------*/
extern uint8_t recevie[7];
//key    
struct keys{uint8_t judge_sta;uint8_t key_sta;uint8_t single_flag;uint8_t long_flag;uint8_t key_time;
};
/*key define-------------------------------------------------------------------*/   
#define B1_Port GPIOB
#define B2_Port GPIOB
#define B3_Port GPIOB  
#define B4_Port GPIOA#define B1_Pin  GPIO_PIN_0
#define B2_Pin  GPIO_PIN_1
#define B3_Pin  GPIO_PIN_2   
#define B4_Pin  GPIO_PIN_0#define Long_time  200   //2s
#define Short_time 50    //0.5s//led
void led_set(uint8_t led_dis);void led_2_toggle(void);
//key_control
void key_control(void);
void dispaly_init(void);
void menu_display(void);
void fre_2hz_duty_10_set(void);#ifdef __cplusplus
}
#endif
#endif

四、串口中断接收

本题目要求接收7个ASCII码字符

定义uint8_t 类型接收数组

uint8_t recevie[7];

在while(1)前开启串口接收中断函数，接收7个字符后进入中断服务函数

HAL_UART_Receive_IT(&huart1,recevie,7);

根据中断类型，调用中断回调函数

下面展示中断服务函数

//串口接收完成中断回调服务函数
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{if(huart->Instance == USART1){led_set(0xaa);if(((recevie[0]-'0')*100+(recevie[1]-'0')*10+(recevie[2]-'0') == password)&&(recevie[3]) == '-'){password = (recevie[4]-'0')*100+(recevie[5]-'0')*10+(recevie[6]-'0');}HAL_UART_Receive_IT(&huart1,recevie,7);}
}

五、LED灯闪烁问题

计时应该是正确的5s

    if(htim->Instance == TIM7){static uint16_t time = 0;if(password_valid == 1){password_err_3 = 0;led_set(0x01);F= 2000;fre_2hz_duty_10_set();if(time>= 50-1){password_valid = 0;led_set(0x00);time = 0;menu = MENU_PSD;B1 = '@';B2 = '@';B3 = '@';}else{time ++;}}else if(password_err_3 == 1){static uint8_t cnt = 0;cnt ++;cnt %= 2;//led2翻转if(cnt == 0){led_set(0x02);}else{led_set(0x00);}//5s后接触报警if(time>= 50-1){password_err_3 = 0;led_set(0x00);time = 0;  //5s计时清零cnt = 0;}else{time ++;   //计时++}F= 1000;fre_1hz_duty_50_set();//方波1hz}else{time = 0;fre_1hz_duty_50_set();//方波1hz}                     }

六、总结

本次只写一个usr.c usr.h，发现确实方便了许多！！相较于14届难度较小

比照LCD的cubemx配置引脚的时候，记得配置PD2（led锁存器引脚）

复制其他.h时后记得更改预编译

#ifndef __USR_H__        //记得更改
#define __USR_H__#ifdef __cplusplus
extern "C" {
#endif/* Includes ------------------------------------------------------------------*/
#include "main.h"#ifdef __cplusplus
}
#endif
#endif

如果没有改为__USR_H__,跳转函数跳转不进去usr.c文件，会显示C99_warning