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蓝桥杯单片机组第十二届省赛第二批次

news 来源：原创 2025/9/8 1:32:20

前言
第十二届省赛涉及知识点：NE555频率数据读取，NE555频率转换周期，PCF8591同时测量光敏电阻和电位器的电压、按键长短按判断。

本试题涉及模块较少，题目不难，基本上准备充分的都能完整的实现每一个功能，并且板子上都能实现，一个恶心的地方就是通过PCF8591只采集一条通道的电压值是没有问题的，但是同时采集两条通道的时候，会出现问题，在另一篇文章已经给出了解决方法：
PCF8591一次测量多个通道导致数值不准确解决方法

附件：蓝桥杯单片机组第十二届省赛第二批次

一、阅读题目，了解性能需求

可以得出以下信息：

板子上需要将P34与SIGNAL通过跳线帽短接读取NE555产生的频率。
NE555部分已经详细地讲过如何实现了，可以点击下方传送门查阅：
传送门：NE555模块

在这里插入图片描述

数码管显示的频率、周期和电压值都是实际值，题目中说到的采集频率和电压只有在LED灯有用。

二、底层函数搭建

1.初始化

Init.h

#ifndef __Init_H__
#define __Init_H__void Init();#endif

Init.c

#include <STC15F2K60S2.H>
void Init()
{P0 = 0xff;P2 = P2 & 0x1f | 0x80;P2 &= 0x1f;P0 = 0x00;P2 = P2 & 0x1f | 0xa0;P2 &= 0x1f;
}

2.NE555和独立按键

由于NE555是通过P34引脚测量的，所以需要修改独立按键的底层代码。(屏蔽P34)
Key.h

#include <STC15F2K60S2.H>
#ifndef __Key_H__
#define __Key_H__unsigned char KeyDisp();#endif

Key.c

#include <STC15F2K60S2.H>unsigned char KeyDisp()
{unsigned char temp = 0;P44 = 0;P42 = 1;P35 = 1;if(P30 == 0)temp = 7;if(P31 == 0)temp = 6;if(P32 == 0)temp = 5;if(P33 == 0)temp = 4;	return temp;
}

定时器部分

void Timer0_Init(void)		//0毫秒@12.000MHz
{TMOD &= 0xF0;			//设置定时器模式TMOD |= 0x05;TL0 = 0;				//设置定时初始值TH0 = 0;				//设置定时初始值TF0 = 0;				//清除TF0标志TR0 = 1;				//定时器0开始计时
}void Timer1_Init(void)		//1毫秒@12.000MHz
{AUXR &= 0xBF;			//定时器时钟12T模式TMOD &= 0x0F;			//设置定时器模式TL1 = 0x18;				//设置定时初始值TH1 = 0xFC;				//设置定时初始值TF1 = 0;				//清除TF1标志TR1 = 1;				//定时器1开始计时ET1 = 1;				//使能定时器1中断EA = 1;
}void Timer1_Isr(void) interrupt 3
{systick++;if(++SegPos == 8)SegPos = 0;SegDisp(SegPos, SegBuf[SegPos], SegPoint[SegPos]);if(++Time_1s == 1000){Time_1s = 0;f = (TH0 << 8) | TL0;TH0 = TL0 = 0;}
}

2.数码管部分

数码管底层代码引入
Seg.h

#ifndef __Seg_H__
#define __Seg_H__void SegDisp(unsigned char wela, unsigned char dula, unsigned char point);#endif

Seg.c

#include <STC15F2K60S2.H>code unsigned char Seg_Table[] =
{
0xc0, //0
0xf9, //1
0xa4, //2
0xb0, //3
0x99, //4
0x92, //5
0x82, //6
0xf8, //7
0x80, //8
0x90, //9
0xff, //空
0xbf, //-
0x8e, //F
0xc1, //U
0xc8 //n
};void SegDisp(unsigned char wela, unsigned char dula, unsigned char point)
{P0 = 0xff;P2 = P2 & 0x1f | 0xe0;P2 &= 0x1f;P0 = (0x01 << wela);P2 = P2 & 0x1f | 0xc0;P2 &= 0x1f;P0 = Seg_Table[dula];if(point)P0 &= 0x7f;P2 = P2 & 0x1f | 0xe0;P2 &= 0x1f;
}

3.Led部分

Led.h

#ifndef __Led_H__
#define __Led_H__void LedDisp(unsigned char *ucLed);#endif

Led.c

#include <STC15F2K60S2.H>void LedDisp(unsigned char *ucLed)
{unsigned char i, temp = 0x00;static unsigned char temp_old = 0xff;for(i = 0; i < 8; i++)temp |= (ucLed[i] << i);if(temp != temp_old){P0 = ~temp;P2 = P2 & 0x1f | 0x80;P2 &= 0x1f;temp_old = temp;}
}

4.PCF8591部分

注：本篇文章中解决多通道读取采用的是连续读取两次电压值，舍弃第一个电压值的方法。
pcf8591.h

#ifndef __pcf8591_H__
#define __pcf8591_H__unsigned char AD_Read(unsigned char add);#endif

pcf8591.c

#include <STC15F2K60S2.H>
#include <intrins.h>/*	#   I2C代码片段说明1. 	本文件夹中提供的驱动代码供参赛选手完成程序设计参考。2. 	参赛选手可以自行编写相关代码或以该代码为基础，根据所选单片机类型、运行速度和试题中对单片机时钟频率的要求，进行代码调试和修改。
*/
#define DELAY_TIME	5
sbit scl = P2^0;
sbit sda = P2^1;
//
static void I2C_Delay(unsigned char n)
{do{_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();		}while(n--);      	
}//
void I2CStart(void)
{sda = 1;scl = 1;I2C_Delay(DELAY_TIME);sda = 0;I2C_Delay(DELAY_TIME);scl = 0;    
}//
void I2CStop(void)
{sda = 0;scl = 1;I2C_Delay(DELAY_TIME);sda = 1;I2C_Delay(DELAY_TIME);
}//
void I2CSendByte(unsigned char byt)
{unsigned char i;for(i=0; i<8; i++){scl = 0;I2C_Delay(DELAY_TIME);if(byt & 0x80){sda = 1;}else{sda = 0;}I2C_Delay(DELAY_TIME);scl = 1;byt <<= 1;I2C_Delay(DELAY_TIME);}scl = 0;  
}//
unsigned char I2CReceiveByte(void)
{unsigned char da;unsigned char i;for(i=0;i<8;i++){   scl = 1;I2C_Delay(DELAY_TIME);da <<= 1;if(sda) da |= 0x01;scl = 0;I2C_Delay(DELAY_TIME);}return da;    
}//
unsigned char I2CWaitAck(void)
{unsigned char ackbit;scl = 1;I2C_Delay(DELAY_TIME);ackbit = sda; scl = 0;I2C_Delay(DELAY_TIME);return ackbit;
}//
void I2CSendAck(unsigned char ackbit)
{scl = 0;sda = ackbit; I2C_Delay(DELAY_TIME);scl = 1;I2C_Delay(DELAY_TIME);scl = 0; sda = 1;I2C_Delay(DELAY_TIME);
}unsigned char AD_Read(unsigned char add) 
{unsigned char temp;I2CStart();I2CSendByte(0x90);I2CWaitAck();I2CSendByte(add);I2CWaitAck();I2CStart();I2CSendByte(0x91);I2CWaitAck();temp = I2CReceiveByte(); I2CSendAck(1);I2CStop();// 再次读取I2CStart();I2CSendByte(0x90);I2CWaitAck();I2CSendByte(add);I2CWaitAck();I2CStart();I2CSendByte(0x91);I2CWaitAck();temp = I2CReceiveByte();I2CSendAck(1);I2CStop();return temp;
}

5.main.c

#include <STC15F2K60S2.H>
#include "Init.h"
#include "LED.h"
#include "Key.h"
#include "Seg.h"
#include "pcf8591.h"/* 变量声明区 */
unsigned char Key_Slow; //按键减速变量 10ms 
unsigned char Key_Val, Key_Down, Key_Up, Key_Old; //按键检测四件套
unsigned int Seg_Slow; //数码管减速变量 500ms
unsigned char Seg_Buf[] = {10,10,10,10,10,10,10,10,10,10};//数码管缓存数组
unsigned char Seg_Pos;//数码管缓存数组专用索引
unsigned char Seg_Point[8] = {0,0,0,0,0,0,0,0};//数码管小数点使能数组
unsigned char ucLed[8] = {0,0,0,0,0,0,0,0};//LED显示数据存放数组
unsigned int Time_1s, f;/* 按键处理函数 */
void Key_Proc()
{if(Key_Slow) return;Key_Slow = 1; //按键减速Key_Val = Key();Key_Down = Key_Val & ~Key_Old;	 Key_Up = ~Key_Val & Key_Old;Key_Old = Key_Val;}/* 信息处理函数 */
void Seg_Proc()
{if(Seg_Slow) return;Seg_Slow = 1; //数码管减速}/* 其他显示函数 */
void Led_Proc()
{}/* 定时器0只用于计数 */
void Timer0_Init(void)		//1毫秒@12.000MHz
{TMOD &= 0xF0;			//设置定时器模式TMOD |= 0x05;TL0 = 0;				//设置定时初始值TH0 = 0;				//设置定时初始值TF0 = 0;				//清除TF0标志TR0 = 1;				//定时器0开始计时
}/* 定时器1用于计时 */
void Timer1_Init(void)		//1毫秒@12.000MHz
{AUXR &= 0xBF;			//定时器时钟12T模式TMOD &= 0x0F;			//设置定时器模式TL1 = 0x18;				//设置定时初始值TH1 = 0xFC;				//设置定时初始值TF1 = 0;				//清除TF1标志TR1 = 1;				//定时器1开始计时ET1 = 1;EA = 1;
}/* 定时器1中断服务函数 */
void Timer1_Server() interrupt 3
{/* NE555 */if(++Time_1s == 1000){Time_1s = 0;f = (TH0 << 8) | TL0;TH0 = TL0 = 0;}
}void main()
{Init();Timer0_Init();Timer1_Init();while(1){Key_Proc(); Seg_Proc();Led_Proc();}
}

三、数码管部分

在这里插入图片描述
老样子，定义SegMode变量来控制三个页面，SegMode值为0时为频率显示页面，为1时为周期设置界面，为2时为电压显示界面

在数码管Seg.c底层函数的段码表已经包含F、N、U和-的段码表了

1.频率显示页面

NE555测量频率的上限值是五位数，题目要求七位显示频率数据，要求高位为0熄灭，可以直接默认前两位数码管熄灭，再对后五个数码管进行高位熄灭，高位熄灭的实现逻辑如下：

unsigned char i = 0;
while(SegBuf[i] == 0)//循环条件：SegBuf[i]不为0时退出
{SegBuf[i] = 10;if(++i == 7)break;
}

数码管实现如下：

void SegProc()
{unsigned char i;switch(SegMode){case 0:SegPoint[5] = 0;SegBuf[0] = 12;SegBuf[1] = 10;SegBuf[2] = 10;SegBuf[3] = f / 10000 % 10;SegBuf[4] = f / 1000 % 10;SegBuf[5] = f / 100 % 10;SegBuf[6] = f / 10 % 10;SegBuf[7] = f % 10;i = 3;while(!SegBuf[i]){SegBuf[i] = 10;if(++i == 7)break;}break;}
}

2.周期显示页面

从题目可以得到，显示的周期是频率的倒数，也就是T= $\frac{1}{f}$ ，单位为us，而1s = 100 0000us，所以转换周期时要省上10 $^6$ 。代码实现如下：

case 1:T = 1000000 / f;SegBuf[0] = 14;SegBuf[1] = T / 1000000 % 10;SegBuf[2] = T / 100000 % 10;SegBuf[3] = T / 10000 % 10;SegBuf[4] = T / 1000 % 10;SegBuf[5] = T / 100 % 10;SegBuf[6] = T / 10 % 10;SegBuf[7] = T % 10;i = 1;while(!SegBuf[i]){SegBuf[i] = 10;if(++i == 7)break;}
break;

3.电压显示页面

电压读取

这边给出两种方法
方法一：定义float型变量

idata float RD1_100x, RB2_100x;
idata bit ChannelMode;void ADCProc()
{RD1_100x = AD_Read(0x01) / 51.0; RB2_100x = AD_Read(0x03) / 51.0; 
}void SegProc()
{case 2:SegBuf[0] = 13;SegBuf[1] = 11;SegBuf[2] = !ChannelMode ? 1 : 3;SegBuf[3] = 10;SegBuf[4] = 10;SegBuf[5] = !ChannelMode ? RD1_100x % 10 : RB2_100x % 10;SegPoint[5] = 1;SegBuf[6] = !ChannelMode ? RD1_100x * 10 % 10: RB2_100x * 10 % 10;SegBuf[7] = !ChannelMode ? RD1_100x * 100 % 10 : RB2_100x * 100 % 10;break;
}

方法二：定义unsigned int型变量接受读取的电压值放大100倍后的值

idata u16 RD1_100x, RB2_100x;
void ADCProc()
{RD1_100x = AD_Read(0x01) * 100 / 51; RB2_100x = AD_Read(0x03) * 100 / 51; 
}
void SegProc()
{case 2:SegBuf[0] = 13;SegBuf[1] = 11;SegBuf[2] = !ChannelMode ? 1 : 3;SegBuf[3] = 10;SegBuf[4] = 10;SegBuf[5] = !ChannelMode ? RD1_100x / 100 : RB2_100x / 100;SegPoint[5] = 1;SegBuf[6] = !ChannelMode ? RD1_100x / 10 % 10 : RB2_100x / 10 % 10;SegBuf[7] = !ChannelMode ? RD1_100x % 10 : RB2_100x % 10;break;
}

4.数码管完整代码：

void SegProc()
{unsigned char i;if(Seg_Slow) return;Seg_Slow = 1; //数码管减速switch(SegMode){case 0:SegPoint[5] = 0;SegBuf[0] = 12;SegBuf[1] = 10;SegBuf[2] = 10;SegBuf[3] = f / 10000 % 10;SegBuf[4] = f / 1000 % 10;SegBuf[5] = f / 100 % 10;SegBuf[6] = f / 10 % 10;SegBuf[7] = f % 10;i = 3;while(!SegBuf[i]){SegBuf[i] = 10;if(++i == 7)break;}break;case 1:T = 1000000 / f;SegBuf[0] = 14;SegBuf[1] = T / 1000000 % 10;SegBuf[2] = T / 100000 % 10;SegBuf[3] = T / 10000 % 10;SegBuf[4] = T / 1000 % 10;SegBuf[5] = T / 100 % 10;SegBuf[6] = T / 10 % 10;SegBuf[7] = T % 10;i = 1;while(!SegBuf[i]){SegBuf[i] = 10;if(++i == 7)break;}break;case 2:SegBuf[0] = 13;SegBuf[1] = 11;SegBuf[2] = !ChannelMode ? 1 : 3;SegBuf[3] = 10;SegBuf[4] = 10;SegBuf[5] = !ChannelMode ? RD1_100x / 100 : RB2_100x / 100;SegPoint[5] = 1;SegBuf[6] = !ChannelMode ? RD1_100x / 10 % 10 : RB2_100x / 10 % 10;SegBuf[7] = !ChannelMode ? RD1_100x % 10 : RB2_100x % 10;break;}
}

四、按键部分

在这里插入图片描述
S4和S5的实现很简单，直接给出代码
S6的功能是任意界面下按下S6后，保存电位器的电压数据到电位器缓存变量中。

idata u16 RD1_100x, RB2_100x;
idata u16 RB2_100x_keep, f_keep;void KeyProc()
{KeyVal = KeyDisp();KeyDown = KeyVal & ~KeyOld;KeyUp = ~KeyVal & KeyOld;KeyOld = KeyVal;switch(KeyDown){case 4:if(++SegMode == 3){SegMode = 0;ChannelMode = 0;}break;case 5:ChannelMode ^= 1;break;case 6:RB2_100x_keep = RB2_100x;break;}
}

S7的功能是短按保存频率，长按打开/关闭Led
这个也是很常考的点了，也很简单
先定义一个Time_1000ms的unsigned int型变量放入定时器1中定时，当超过1000ms时置为1000（防止长按太久数据溢出），然后在设置一个按下S7的变量idata bit型变量CountFlag，当S7按下，CountFlag置1，定时器开始计时，松开S7，CountFlag置为0，计数值清零

注意：NE555和长按S7都是以定时1s为判断，因此定义变量时不要重复定义！

void KeyProc()
{KeyVal = KeyDisp();KeyDown = KeyVal & ~KeyOld;KeyUp = ~KeyVal & KeyOld;KeyOld = KeyVal;if(KeyDown == 7)CountFlag = 1;if(KeyUp == 7){CountFlag = 0;if(Time_1000ms >= 1001){LedFlag = !LedFlag;}elsef_keep = f;}
}void Timer1_Isr(void) interrupt 3
{systick++;if(++SegPos == 8)SegPos = 0;SegDisp(SegPos, SegBuf[SegPos], SegPoint[SegPos]);if(++Time_1s == 1000){Time_1s = 0;f = (TH0 << 8) | TL0;TH0 = TL0 = 0;}if(CountFlag){if(++Time_1000ms >= 1001)Time_1000ms = 1001;}elseTime_1000ms = 0;
}

按键完整代码

void KeyProc()
{KeyVal = KeyDisp();KeyDown = KeyVal & ~KeyOld;KeyUp = ~KeyVal & KeyOld;KeyOld = KeyVal;if(KeyDown == 7)CountFlag = 1;if(KeyUp == 7){CountFlag = 0;if(Time_1000ms >= 1001){LedFlag = !LedFlag;}elsef_keep = f;}switch(KeyDown){case 4:if(++SegMode == 3){SegMode = 0;ChannelMode = 0;}break;case 5:ChannelMode ^= 1;break;case 6:RB2_100x_keep = RB2_100x;break;}
}

五、Led部分

在这里插入图片描述
Led的实现完全没有难度
直接给出代码

void LedProc()
{if(LedFlag == 0){ucLed[0] = (RB2_100x > RB2_100x_keep);ucLed[1] = (f > f_keep);ucLed[2] = (SegMode == 0);ucLed[3] = (SegMode == 1);ucLed[4] = (SegMode == 2);}else{ucLed[0] = 0;ucLed[1] = 0;ucLed[2] = 0;ucLed[3] = 0;ucLed[4] = 0;}LedDisp(ucLed);
}

六、完整代码

#include <STC15F2K60S2.H>
#include "Init.h"
#include "LED.h"
#include "Key.h"
#include "Seg.h"
#include "pcf8591.h"/* 变量声明区 */
typedef unsigned char u8;
typedef unsigned int u16;idata u8 KeyVal, KeyDown, KeyUp, KeyOld;
idata u8 SegPos;
idata u8 SegMode;idata u16 f, Time_1s;
idata u16 T;
idata u16 RD1_100x, RB2_100x;
idata u16 RB2_100x_keep, f_keep;
idata u16 Time_1000ms;pdata u8 SegBuf[8] = {10,10,10,10,10,10,10,10};
pdata u8 SegPoint[8] = {0,0,0,0,0,0,0,0};
pdata u8 ucLed[8] = {0,0,0,0,0,0,0,0};idata bit ChannelMode;
idata bit CountFlag;
idata bit LedFlag;/* 按键处理函数 */
void Key_Proc()
{if(Key_Slow) return;Key_Slow = 1; //按键减速KeyVal = KeyDisp();KeyDown = KeyVal & ~KeyOld;KeyUp = ~KeyVal & KeyOld;KeyOld = KeyVal;if(KeyDown == 7)CountFlag = 1;if(KeyUp == 7){CountFlag = 0;if(Time_1000ms >= 1001){LedFlag = !LedFlag;}elsef_keep = f;}switch(KeyDown){case 4:if(++SegMode == 3){SegMode = 0;ChannelMode = 0;}break;case 5:ChannelMode ^= 1;break;case 6:RB2_100x_keep = RB2_100x;break;}
}/* 信息处理函数 */
void Seg_Proc()
{unsigned char i;if(Seg_Slow) return;Seg_Slow = 1; //数码管减速switch(SegMode){case 0:SegPoint[5] = 0;SegBuf[0] = 12;SegBuf[1] = 10;SegBuf[2] = 10;SegBuf[3] = f / 10000 % 10;SegBuf[4] = f / 1000 % 10;SegBuf[5] = f / 100 % 10;SegBuf[6] = f / 10 % 10;SegBuf[7] = f % 10;i = 3;while(!SegBuf[i]){SegBuf[i] = 10;if(++i == 7)break;}break;case 1:T = 1000000 / f;SegBuf[0] = 14;SegBuf[1] = T / 1000000 % 10;SegBuf[2] = T / 100000 % 10;SegBuf[3] = T / 10000 % 10;SegBuf[4] = T / 1000 % 10;SegBuf[5] = T / 100 % 10;SegBuf[6] = T / 10 % 10;SegBuf[7] = T % 10;i = 1;while(!SegBuf[i]){SegBuf[i] = 10;if(++i == 7)break;}break;case 2:SegBuf[0] = 13;SegBuf[1] = 11;SegBuf[2] = !ChannelMode ? 1 : 3;SegBuf[3] = 10;SegBuf[4] = 10;SegBuf[5] = !ChannelMode ? RD1_100x / 100 : RB2_100x / 100;SegPoint[5] = 1;SegBuf[6] = !ChannelMode ? RD1_100x / 10 % 10 : RB2_100x / 10 % 10;SegBuf[7] = !ChannelMode ? RD1_100x % 10 : RB2_100x % 10;break;}
}/* 其他显示函数 */
void Led_Proc()
{if(LedFlag == 0){ucLed[0] = (RB2_100x > RB2_100x_keep);ucLed[1] = (f > f_keep);ucLed[2] = (SegMode == 0);ucLed[3] = (SegMode == 1);ucLed[4] = (SegMode == 2);}else{ucLed[0] = 0;ucLed[1] = 0;ucLed[2] = 0;ucLed[3] = 0;ucLed[4] = 0;}LedDisp(ucLed);
}/* 定时器0只用于计数 */
void Timer0_Init(void)		//1毫秒@12.000MHz
{TMOD &= 0xF0;			//设置定时器模式TMOD |= 0x05;TL0 = 0;				//设置定时初始值TH0 = 0;				//设置定时初始值TF0 = 0;				//清除TF0标志TR0 = 1;				//定时器0开始计时
}/* 定时器1用于计时 */
void Timer1_Init(void)		//1毫秒@12.000MHz
{AUXR &= 0xBF;			//定时器时钟12T模式TMOD &= 0x0F;			//设置定时器模式TL1 = 0x18;				//设置定时初始值TH1 = 0xFC;				//设置定时初始值TF1 = 0;				//清除TF1标志TR1 = 1;				//定时器1开始计时ET1 = 1;EA = 1;
}/* 定时器1中断服务函数 */
void Timer1_Server() interrupt 3
{/* NE555 */if(++Time_1s == 1000){Time_1s = 0;f = (TH0 << 8) | TL0;TH0 = TL0 = 0;}if(CountFlag){if(++Time_1000ms >= 1001)Time_1000ms = 1001;}elseTime_1000ms = 0;
}void main()
{Init();Timer0_Init();Timer1_Init();while(1){Key_Proc(); Seg_Proc();Led_Proc();}
}

本篇文章中的代码已经通过4T测试
在这里插入图片描述

其余模块代码请自行添加到工程中即可运行，本篇文章仅提供一种实现思路，如有模块代码无法实现或者与题目要求相违，请移步评论区指出或私信我，看到会及时回复。
每周会更新两篇模拟赛、省赛或国赛的文章，敬请期待。