Analysis of the problems of the 12th Blue Bridge Cup single chip microcomputer provincial competition

I have just finished this topic , Let's take a look 2021 The title of the year , What's wrong , I hope you will correct me .

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First of all, there are still three modules （ Nixie tube 、LED、 Key ） , also DS18B20,DA Output . I have written some provincial competition questions , These are the things that I test every time , As long as every module has been practiced , It shouldn't be difficult . I found that from 2020 Year begins , Although I still use four buttons , But it becomes a matrix button , Before, there were independent buttons .

1 The nixie tube shows

The digital tube has a temperature display , Parameter setting and DA Output three interfaces , adopt s4 To switch .

2 LED

When in mode 1 In the state of L1 bright , When the nixie tube is in the temperature display interface L2 bright , In the parameter setting interface L3 bright ,DA When outputting the interface L4 bright .

3 Key module

Using a matrix keyboard ,s4 It is the switching of three interfaces ,s8,s9 Is the addition and subtraction of temperature parameters 1, There is a small hole here, that is, the set temperature parameter takes effect only when you exit the parameter setting interface , This requires defining the variables of two temperature parameters , One is used to add and subtract temperature parameters , Assign a value to another variable when exiting the temperature parameter interface , The other is used to compare the size with the real-time temperature .s5 There are two models , Model a The real-time temperature is less than the temperature parameter DA Output 0v, Otherwise output 5v. Model 2 Output voltage according to the relationship given in the figure .

4 DS18B20

Is to rewrite the underlying driver code （onewire）, Then put it in the timer , Read every once in a while .

5 DAC

Is to rewrite the underlying driver code （IIC）.

onewire.c

#include"onewire.h"

sbit DQ = P1^4;  

void Delay_OneWire(unsigned int t)  
{
	t*=12;
	while(t--);
}

void Write_DS18B20(unsigned char dat)
{
	unsigned char i;
	for(i=0;i<8;i++)
	{
		DQ = 0;
		DQ = dat&0x01;
		Delay_OneWire(5);
		DQ = 1;
		dat >>= 1;
	}
	Delay_OneWire(5);
}

unsigned char Read_DS18B20(void)
{
	unsigned char i;
	unsigned char dat;
  
	for(i=0;i<8;i++)
	{
		DQ = 0;
		dat >>= 1;
		DQ = 1;
		if(DQ)
		{
			dat |= 0x80;
		}	    
		Delay_OneWire(5);
	}
	return dat;
}

bit init_ds18b20(void)
{
  	bit initflag = 0;
  	
  	DQ = 1;
  	Delay_OneWire(12);
  	DQ = 0;
  	Delay_OneWire(80);
  	DQ = 1;
  	Delay_OneWire(10); 
    initflag = DQ;     
  	Delay_OneWire(5);
  
  	return initflag;
}

unsigned int Get_temp()
{
	unsigned int result;
	unsigned char high,low;
	
	init_ds18b20();
	Write_DS18B20(0xcc);
	Write_DS18B20(0x44);
	
	init_ds18b20();
	Write_DS18B20(0xcc);
	Write_DS18B20(0xbe);
	
	low=Read_DS18B20();
	high=Read_DS18B20();
	
	result=(high<<8)|low;
	result*=6.25;
	return result;
}

onewire.h

#ifndef _ONEWIRE_H_
#define _ONEWIRE_H_

#include<stc15f2k60s2.h>

void Delay_OneWire(unsigned int t);
void Write_DS18B20(unsigned char dat);
unsigned char Read_DS18B20(void);
bit init_ds18b20(void);
unsigned int Get_temp();

#endif

IIC.c

#include"IIC.h"

#define DELAY_TIME 5

#define SlaveAddrW 0xA0
#define SlaveAddrR 0xA1

sbit SDA = P2^1;  
sbit SCL = P2^0; 

void IIC_Delay(unsigned char i)
{
    do{_nop_();}
    while(i--);        
}

void IIC_Start(void)
{
    SDA = 1;
    SCL = 1;
    IIC_Delay(DELAY_TIME);
    SDA = 0;
    IIC_Delay(DELAY_TIME);
    SCL = 0;	
}

void IIC_Stop(void)
{
    SDA = 0;
    SCL = 1;
    IIC_Delay(DELAY_TIME);
    SDA = 1;
    IIC_Delay(DELAY_TIME);
}

bit IIC_WaitAck(void)
{
    bit ackbit;
	
    SCL  = 1;
    IIC_Delay(DELAY_TIME);
    ackbit = SDA;
    SCL = 0;
    IIC_Delay(DELAY_TIME);
    return ackbit;
}

void IIC_SendByte(unsigned char byt)
{
    unsigned char i;

    for(i=0; i<8; i++)
    {
        SCL  = 0;
        IIC_Delay(DELAY_TIME);
        if(byt & 0x80) SDA  = 1;
        else SDA  = 0;
        IIC_Delay(DELAY_TIME);
        SCL = 1;
        byt <<= 1;
        IIC_Delay(DELAY_TIME);
    }
    SCL  = 0;  
}

void DA_out(unsigned char date)
{
	IIC_Start();
	IIC_SendByte(0x90);
	IIC_WaitAck();
	IIC_SendByte(0x40);
	IIC_WaitAck();
	IIC_SendByte(date);
	IIC_WaitAck();
	IIC_Stop();
}

IIC.h

#ifndef _IIC_H_
#define _IIC_H_

#include<stc15f2k60s2.h>
#include<intrins.h>

void IIC_Delay(unsigned char i);
void IIC_Start(void);
void IIC_Stop(void);
bit IIC_WaitAck(void);
void IIC_SendByte(unsigned char byt);
void DA_out(unsigned char date);

#endif

init.c

#include"init.h"

#define u8 unsigned char 
#define u16 unsigned int
#define state_0 0
#define state_1 1
#define state_2 2
	
u8 code tab[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0xbf,0xff,0xc6,0x8c,0x88};
u8 seg[]={11,11,11,11,11,11,11,11};
static u8 segaddr=0;
u8 value=0;
extern u8 mode;

void all_init()    // Turn off irrelevant peripherals 
{
	P2=(P2&0x1f)|0x80;P0=0xff;P2&=0x1f;
	
	P2=(P2&0x1f)|0xa0;P04=0;P06=0;P2&=0x1f;
	
	P2=(P2&0x1f)|0xc0;P0=0x00;P2&=0x1f;
	
	P2=(P2&0x1f)|0xe0;P0=0xff;P2&=0x1f;
}

void display()     // Nixie tube display function 
{
	P2=(P2&0x1f)|0xe0;P0=0xff;P2&=0x1f;
	
	P2=(P2&0x1f)|0xc0;P0=1<<segaddr;P2&=0x1f;
	
	if(mode!=2&&segaddr==5)
	{
		P2=(P2&0x1f)|0xe0;P0=tab[seg[segaddr]]&0x7f;P2&=0x1f;
	}
	else
	{
		P2=(P2&0x1f)|0xe0;P0=tab[seg[segaddr]];P2&=0x1f;
	}
	if(++segaddr==8)segaddr=0;
}

u8 Read_key()    // Matrix keyboard 
{
	static u8 key_press,key_num=0,key_state=0;
	key_press=P3&0x0f;
	switch(key_state)
	{
		case state_0:
			if(key_press!=0x0f)
				key_state=state_1;
		break;
		case state_1:
			if(key_press!=0x0f)
			{
				if((key_press & 0x08)==0) key_num=4;
				if((key_press & 0x04)==0) key_num=5;
				if((key_press & 0x02)==0) key_num=6;
				if((key_press & 0x01)==0) key_num=7;
				key_state=state_2;
			}
			else
				key_state=state_0;
		break;
		case state_2:
			if(key_press==0x0f)
				key_state=state_0;
		break;
	}
	value=key_num;
	key_num=0;
	return value;
}

void Timer0Init(void)		
{
	AUXR |= 0x80;		
	TMOD &= 0xF0;		
	TL0 = 0xCD;		
	TH0 = 0xD4;		
	TF0 = 0;		
	TR0 = 1;
  ET0 = 1;
  EA = 1;	
}

init.h

#ifndef _INIT_H_
#define _INIT_H_

#include<stc15f2k60s2.h>

void all_init();
void display();
unsigned char Read_key();
void Timer0Init(void);

#endif

jm.c

#include"jm.h"
#include"IIC.h"

#define u8 unsigned char 
#define u16 unsigned int
	
u16 TT=2500,TF=2500;
	
extern u8 mode,seg[];             // extern Indicates that this variable is defined elsewhere , To quote... Here 
extern u16 temp,RB2;
extern bit MS;

void jm4()
{
	if(mode==1)               // Temperature display interface 
	{
		seg[0]=12;
		seg[1]=11;
		seg[2]=11;
		seg[3]=11;
		seg[4]=temp/1000;
		seg[5]=temp/100%10;
		seg[6]=temp/10%10;
		seg[7]=temp%10;
	}
	else if(mode==2)          // Parameter setting interface 
	{
		seg[0]=13;
		seg[1]=11;
		seg[2]=11;
		seg[3]=11;
		seg[4]=11;
		seg[5]=11;
		seg[6]=TF/1000;
		seg[7]=TF/100%10;
	}
	else if(mode==3)        //DA Output interface 
	{
		seg[0]=14;
		seg[1]=11;
	  seg[2]=11;
		seg[3]=11;
		seg[4]=11;
		seg[5]=RB2/100;
		seg[6]=RB2/10%10;
		seg[7]=RB2%10;
	}
}

void jm5()            // Mode switching function 
{
	if(MS==0)
	{
		if(temp<TT)
		{
			DA_out(0);
			RB2=0;
		}
		else
		{
			DA_out(255);
			RB2=500;
		}
	}
	else
	{
		if(temp<=2000)
		{
			DA_out(196);
			RB2=100;
		}
		else if(temp>2000&&temp<=4000)
		{
			DA_out((0.15*temp-200)*51.0);
			RB2=(u16)(0.15*temp-200+0.5);
		}
		else
		{
			DA_out(204);
			RB2=400;
		}
	}
}

void jm8()
{
	if(mode==2)TF-=100;
}

void jm9()
{
	if(mode==2)TF+=100;
}

void LED()           //LED Show function 
{
	u8 i=0xff;
	if(MS==0)
	{
		P2=(P2&0x1f)|0x80;P0=i&0xfe;P2&=0x1f;
	}
	else
	{
		P2=(P2&0x1f)|0x80;P0=i|0x01;P2&=0x1f;
	}
	if(mode==1)
	{
		P2=(P2&0x1f)|0x80;P0=i&0xfd;P2&=0x1f;
	}
	else if(mode==2)
	{
		P2=(P2&0x1f)|0x80;P0=i&0xfb;P2&=0x1f;
	}
	else if(mode==3)
	{
		P2=(P2&0x1f)|0x80;P0=i&0xf7;P2&=0x1f;
	}
}

jm.h

#ifndef _JM_H_
#define _JM_H_

#include<stc15f2k60s2.h>

void jm4();
void jm5();
void jm8();
void jm9();
void LED();

#endif

main.c

#include"init.h"
#include"jm.h"
#include"onewire.h"
#include"IIC.h"

#define u8 unsigned char 
#define u16 unsigned int
	
u8 num=0,temp_count=0;
u8 mode=1;
u16 temp,RB2=325;
bit MS=0,temp_flag=0;
extern TT,TF;
	
void main()
{
	all_init();
	Timer0Init();
	while(1)
	{
		if(temp_flag==1)      // Every time 200ms Read the value of primary temperature 
		{
			temp_flag=0;
			temp=Get_temp();
		}
		num=Read_key();
		switch(num)
		{
			case  4:
				if(++mode==4)mode=1;
			break;
			case  5:
				MS^=1;
			break;
		  case  6:
				jm8();
				TT=TF;
			break;
			case  7:
				jm9();
				TT=TF;
			break;
		}
		jm4();
		jm5();
		LED();
	}
}

void Timer0() interrupt 1
{
	display();
	if(++temp_count==200)
	{
		temp_count=0;
		temp_flag=1;
	}
}

One last time , Each module is relatively simple , The most important programming logic .