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how to use analog sensor+ADC+pic16F877A

Discussion in 'Microcontrollers, Programming and IoT' started by ikram1991, Sep 24, 2013.

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  1. ikram1991

    ikram1991

    43
    0
    May 5, 2013
    Hi guys..I'm still in progress learning about PIC16F877A and I'm just realize that I don't know how to configure analog input..I'm working on project that using analog distance sensor and output LED..when sensor detect something below 40 cm led will turn on..formula that I'm refer in datasheet is Vin * (1023/vref) and when sensor detect something in 40cm 0.7V current will flow to input pin..I'm using MPLAB C compiler..thank you :)
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,497
    2,838
    Jan 21, 2010
    This may help. (first Google hit for "PIC16F877A analog input")
     
  3. ikram1991

    ikram1991

    43
    0
    May 5, 2013
    Thx steve..I already search it around..can i ask something..after setting adcon1 and adcon0 can I direct use the adc value to activate the output..or there need necessery c statement? I'm lost:confused:
     
  4. BobK

    BobK

    7,682
    1,688
    Jan 5, 2010
  5. ligo.george

    ligo.george

    12
    4
    Feb 2, 2013
    There are a lot of tutorials on pic 16f877a availabe on internet..
    [​IMG]
    Code:
    #include<htc.h>
    #include<pic.h>
    
    #define _XTAL_FREQ 8000000
    
    void ADC_Init()
    {
      ADCON0 = 0x41; //ADC Module Turned ON and Clock is selected
      ADCON1 = 0xC0; //All pins as Analog Input
                     //With reference voltages VDD and VSS
    }
    
    unsigned int ADC_Read(unsigned char channel)
    {
      if(channel > 7) //If Invalid channel selected 
        return 0;     //Return 0
    
      ADCON0 &= 0xC5; //Clearing the Channel Selection Bits
      ADCON0 |= channel<<3; //Setting the required Bits
      __delay_ms(2); //Acquisition time to charge hold capacitor
      GO_nDONE = 1; //Initializes A/D Conversion
      while(GO_nDONE); //Wait for A/D Conversion to complete
      return ((ADRESH<<8)+ADRESL); //Returns Result
    }
    
    void main()
    {
      unsigned int a;
      TRISB = 0x00; //PORTB as output
      TRISC = 0x00; //PORTC as output
      TRISA = 0xFF; //PORTA as input
      ADC_Init(); //Initializes ADC Module
    
      do
      {
        a = ADC_Read(4); //Reading Analog Channel 0
        PORTB = a; //Lower 8 bits to PORTB
        PORTC = a>>8; //Higher 2 bits to PORTC
        __delay_ms(100); //Delay
      }while(1); //Infinite Loop
    }
    Source:
    Using ADC of PIC Microcontroller using Hi-Tech C
     
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