Temperature control between two points in single chip microcomputer test

1. Experimental tasks

The voltage value is adjusted by an adjustable resistor as the input of the simulated temperature. When the temperature is lower than 30℃, a long beep and light alarm sound, and when the temperature is higher than 60℃, a short beep and light alarm sound. The measured temperature range is 0-99℃.

2. Circuit diagram

Figure 4.29.1

3. Hardware connection on the system board

a) Connect P1.0-P1.7 in the "MCU System" area to the ABCDEFGH ports in the "Dynamic Digital Display" area using an 8-core cable.

b) Connect P2.0-P2.7 in the "MCU System" area and S1S2S3S4S5S6S7S8 ports in the "Dynamic Digital Display" area using an 8-core cable.

c) Connect P3.0 in the "MCU System" area and the ST terminal in the "Analog-to-Digital Conversion Module" area with a wire.

d) Connect P3.1 in the “MCU System” area and the OE terminal in the “Analog-to-Digital Conversion Module” area with a wire.

e) Connect P3.2 in the "MCU System" area and the EOC terminal in the "Analog-to-Digital Conversion Module" area with a wire.

f) Connect P3.3 in the "MCU System" area and the CLK terminal in the "Analog-to-Digital Conversion Module" area with a wire.

g) Connect the A2A1A0 terminals in the "Analog-to-digital conversion module" area to the GND terminal in the "Power module" area with a wire.

h) Connect the IN0 terminal in the "Analog-to-digital conversion module" area to the VR1 terminal in the "Three-way adjustable voltage module" area with a wire.

i) Connect P0.0-P0.7 in the "MCU System" area to the D0D1D2D3D4D5D6D7 terminals in the "Analog-to-Digital Conversion Module" area using an 8-core cable.

j) Use wires to connect P3.6 and P3.7 in the "MCU System" area to L1 and L2 in the "Eight-way LED Indicator Module" area respectively.

k) Connect P3.5 in the "MCU System" area to the SPK IN port in the "Audio Amplifier Module" area with a wire.

l) Plug the SPK OUT in the “Audio Amplifier Module” area into the audio speaker.

4. Assembly source program

(Omitted) [page]

5. C language source program

#include

unsigned char code dispbitcode[]={0xfe,0xfd,0xfb,0xf7,

                                  0xef,0xdf,0xbf,0x7f};

unsigned char code dispcode[]={0x3f,0x06,0x5b,0x4f,0x66,

                               0x6d,0x7d,0x07,0x7f,0x6f,0x00};

unsigned char dispbuf[8]={10,10,10,10,10,10,0,0};

unsigned char dispcount;

unsigned char getdata;

unsigned int temp;

unsigned char i;

sbit ST=P3^0;

sbit OE=P3^1;

sbit EOC=P3^2;

sbit CLK=P3^3;

sbit LED1=P3^6;

sbit LED2=P3^7;

sbit SPK=P3^5;

bit lowflag;

bit highflag;

unsigned int cnta;

unsigned int cntb;

bit alarmflag;

void main(void)

{

  ST=0;

  OE=0;

  TMOD=0x12;

  TH0=0x216;

  TL0=0x216;

  TH1=(65536-500)/256;

  TL1=(65536-500)%256;

  TR1=1;

  TR0=1;

  ET0=1;

  ET1=1;

  EA=1;

  ST=1;

  ST=0;

  while(1)

    {

      if((lowflag==1) &&(highflag==0))

        {

          LED1=0;

          LED2=1;

        }

        else if((highflag==1) && (lowflag==0))

          {

            LED1=1;

            LED2=0;

          }

          else

            {

              LED1=1;

              LED2=1;

            }

    }

}

void t0(void) interrupt 1 using 0

{

  CLK=~CLK;

}

void t1(void) interrupt 3 using 0

{

  TH1=(65536-500)/256;

  TL1=(65536-500)%256;

       if(EOC==1)

         {

           OE=1;

           getdata=P0;

           OE=0;

           temp=getdata*25;

           temp=temp/64;

           i=6;

           dispbuf[0]=10;

           dispbuf[1]=10;

           dispbuf[2]=10;

           dispbuf[3]=10;

           dispbuf[4]=10;

           dispbuf[5]=10;

           dispbuf[6]=0;

           dispbuf[7]=0;

          while(temp/10)

            {

              dispbuf[i]=temp%10;

              temp=temp/10;

              i++;

            } [page]

          dispbuf[i]=temp;         

           if(getdata<77)

             {

               lowflag=1;

               highflag=0;

             }

             else if(getdata>153)

               {

                 lowflag=0;

                 highflag=1;

               }

               else

                 {

                   lowflag=0;

                   highflag=0;

                 }

           ST=1;

           ST=0;

         }

  P1=dispcode[dispbuf[dispcount]];

  P2=dispbitcode[dispcount];

  dispcount++;

  if(dispcount==8)

    {

      dispcount=0;

    }

  if((lowflag==1) && (highflag==0))

    {

      cnta++;

      if(cnta==800)

        {

          cnta=0;

          alarmflag=~alarmflag;

        }

      if(alarmflag==1)

        {

          SPK=~SPK;

        }

    }

    else if((lowflag==0) && (highflag==1))

      {

      cntb++;

      if(cntb==400)

        {

          cntb=0;

          alarmflag=~alarmflag;

        }

      if(alarmflag==1)

        {

          SPK=~SPK;

        }       

      }

      else

        {

          alarmflag=0;

          cnta=0;

          cntb=0;

        }