当前位置：首页 > java >正文

蓝桥杯备赛按键、LCD、定时器

java 2025/8/16 1:46:47

一、按键原理图

蓝色框中是与对应按键相连接的引脚，红色框中是按键。
将PB0、PB1、PB2、PA0这四个引脚设置为上拉输入模式，即
按键没有按下时，输入得到高电平，(按键断开(未被按下),PB0只会接收来自VDD的高电平)。
按键按下时，输入得到低电平，(按键闭合(被按下),PB0接收来自GND的低电平)。

二、按键扫描函数

三、LCD 显示

fun.c

#include "headfile.h"int count = 0;void led_show(uint8_t led, uint8_t mode)
{HAL_GPIO_WritePin(GPIOD,GPIO_PIN_2,GPIO_PIN_SET);if(mode){	HAL_GPIO_WritePin(GPIOC,GPIO_PIN_8 << (led-1),GPIO_PIN_RESET);}else{HAL_GPIO_WritePin(GPIOC,GPIO_PIN_8 << (led-1),GPIO_PIN_SET);}HAL_GPIO_WritePin(GPIOD,GPIO_PIN_2,GPIO_PIN_RESET);
}uint8_t B1_state; //B1当前状态
uint8_t B1_last_state; //B1上次的状态
uint8_t B2_state;
uint8_t B2_last_state;void key_scan()
{B1_state = HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_0);B2_state = HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_1);if(B1_state == 0 && B1_last_state == 1)//按键B1按下{count++;}if(B2_state == 0 && B2_last_state == 1)//按键B1按下{count--;}B1_last_state = B1_state;B2_last_state = B2_state;
}char date[20]; //因为这块lcd屏幕最多只能展示20个字符
void lcd_show()
{sprintf(date, "        test        ");LCD_DisplayStringLine(Line0, (uint8_t *)date);sprintf(date, "     count: %d      ", count);LCD_DisplayStringLine(Line3, (uint8_t *)date);
}

四、解决led和lcd引脚冲突问题

解决方法

五、定时器

一般用通用定时器

1s中断一次

led闪烁

长按键和短按键

定时器的三个寄存器

长按的意思是：当按键按下时，CNT = 0，（在未松开按键的这段时间里面，CNT的值会一直增加）过来一段时间后，判断CNT是否大于10000，自己定义如果大于，就意味着按键是长按。

lcd高亮显示（fun.c）

#include "headfile.h"int count = 0; //计数
uint8_t led_mode = 0; //mode为1，灯亮；mode为2，灯灭
uint8_t lcd_highshow = 0; //lcd_highshow行进行高亮显示void led_show(uint8_t led, uint8_t mode)
{HAL_GPIO_WritePin(GPIOD,GPIO_PIN_2,GPIO_PIN_SET);if(mode){	HAL_GPIO_WritePin(GPIOC,GPIO_PIN_8 << (led-1),GPIO_PIN_RESET);}else{HAL_GPIO_WritePin(GPIOC,GPIO_PIN_8 << (led-1),GPIO_PIN_SET);}HAL_GPIO_WritePin(GPIOD,GPIO_PIN_2,GPIO_PIN_RESET);}uint8_t B1_state; //B1当前状态
uint8_t B1_last_state = 1; //B1上次的状态
uint8_t B2_state;
uint8_t B2_last_state = 1;
uint8_t B3_state;
uint8_t B3_last_state = 1;
uint8_t B4_state;
uint8_t B4_last_state = 1;void key_scan()
{B1_state = HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_0);B2_state = HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_1);B3_state = HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_2);B4_state = HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_0);//按键B1if(B1_state == 0 && B1_last_state == 1)//按键B1按下{TIM3->CNT  = 0; //计数器清零}else if(B1_state == 0 && B1_last_state == 0)//按键B1一直按着{if(TIM3->CNT >= 10000)//按键B1长按1s{count++;}}else if(B1_state == 1 && B1_last_state == 0) //按键B1松开{if(TIM3->CNT < 10000) //按键B1短按{count += 2;}}
//按键B2if(B2_state == 0 && B2_last_state == 1)//按键B1按下{TIM3->CNT  = 0; //计数器清零}else if(B2_state == 0 && B2_last_state == 0)//按键B1一直按着{if(TIM3->CNT >= 10000)//按键B1长按1s{count--;}}else if(B2_state == 1 && B2_last_state == 0) //按键B1松开{if(TIM3->CNT < 10000) //按键B1短按{count -= 2;}}//按键B3if(B3_state == 0 && B3_last_state == 1)//按键B1按下{led_show(2, 1);}//按键B4if(B4_state == 0 && B4_last_state == 1)//按键B1按下{lcd_highshow++;lcd_highshow %= 3; //lcd_highshow的取值范围为0、1、2led_show(2, 0);}B1_last_state = B1_state;B2_last_state = B2_state;B3_last_state = B3_state;B4_last_state = B4_state;
}char date[20]; //因为这块lcd屏幕最多只能展示20个字符
void lcd_show()
{sprintf(date, "        test        ");LCD_DisplayStringLine(Line0, (uint8_t *)date);if(lcd_highshow == 0){LCD_SetBackColor(Yellow);//设置文字背景色sprintf(date, "     count: %d      ", count);LCD_DisplayStringLine(Line3, (uint8_t *)date);LCD_SetBackColor(Black);sprintf(date, "       para4        ");LCD_DisplayStringLine(Line4, (uint8_t *)date);sprintf(date, "       para5        ");LCD_DisplayStringLine(Line5, (uint8_t *)date);sprintf(date, "       para8        ");LCD_DisplayStringLine(Line8, (uint8_t *)date);}else if(lcd_highshow == 1){sprintf(date, "     count: %d      ", count);LCD_DisplayStringLine(Line3, (uint8_t *)date);LCD_SetBackColor(Yellow);sprintf(date, "       para4        ");LCD_DisplayStringLine(Line4, (uint8_t *)date);LCD_SetBackColor(Black);sprintf(date, "       para5        ");LCD_DisplayStringLine(Line5, (uint8_t *)date);sprintf(date, "       para9        ");LCD_DisplayStringLine(Line9, (uint8_t *)date);}else if(lcd_highshow == 2){sprintf(date, "     count: %d      ", count);LCD_DisplayStringLine(Line3, (uint8_t *)date);sprintf(date, "       para4        ");LCD_DisplayStringLine(Line4, (uint8_t *)date);LCD_SetBackColor(Yellow);sprintf(date, "       para5        ");LCD_DisplayStringLine(Line5, (uint8_t *)date);LCD_SetBackColor(Black);sprintf(date, "12345678901234567890");LCD_DisplayStringLine(Line9, (uint8_t *)date);}led_show(1, led_mode);//放在次处，是为了避免lcd和led引脚冲突
}void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim) //中断回调函数（时间到了，就会触发该函数）
{if(htim->Instance == TIM2) //判断定时器中断来源是定时器2吗{led_mode++;led_mode = led_mode % 2;}
}

查看全文

http://www.xdnf.cn/news/17772.html