Connect ADC with PIC16F877

ADC (Analog to Digital Converter) module is available with a number of PIC MCU modules. ADC is an electronic circuit that converts continuous signals to discrete digital numbers. ADC Library provides you a comfortable work with the module.

Library Routines

• ADC_Init
• ADC_Get_Sample
• ADC_Read

ADC_Init

Prototype	void ADC_Init();
Returns	Nothing.
Description	This routine initializes PIC’s internal ADC module to work with RC clock. Clock determines the time period necessary for performing AD conversion (min 12TAD).
Requires	MCU with built-in ADC module.
Example	ADC_Init(); // Initialize ADC module with default settings

ADC_Get_Sample

Prototype	unsigned ADC_Get_Sample(unsigned short channel);
Returns	10 or 12-bit unsigned value read from the specified channel (MCU dependent).
Description	The function aquires analog value from the specified channel. Parameter channel represents the channel from which the analog value is to be acquired. Refer to the appropriate datasheet for channel-to-pin mapping.   Note : This function doesn't work with the external voltage reference source, only with the internal voltage reference.
Requires	The MCU with built-in ADC module. Prior to using this routine, ADC module needs to be initialized.  Before using the function, be sure to configure the appropriate TRISx bits to designate pins as inputs.
Example	unsigned adc_value; ... adc_value = ADC_Get_Sample(2); // read analog value from ADC module channel 2

ADC_Read

Prototype	unsigned ADC_Read(unsigned short channel);
Returns	10 or 12-bit unsigned value read from the specified channel (MCU dependent).
Description	Initializes PIC’s internal ADC module to work with RC clock. Clock determines the time period necessary for performing AD conversion (min 12TAD). Parameter channel represents the channel from which the analog value is to be acquired. Refer to the appropriate datasheet for channel-to-pin mapping.   Note : This function doesn't work with the external voltage reference source, only with the internal voltage reference.
Requires	The MCU with built-in ADC module. Before using the function, be sure to configure the appropriate TRISx bits to designate pins as inputs.
Example	unsigned tmp; ... tmp = ADC_Read(2); // Read analog value from channel 2

Code Example

This example code reads analog value from channel 2 and displays it on PORTB and PORTC.

unsigned int temp_res;

void main() {
  ANSEL  = 0x04;              // Configure AN2 pin as analog
  ANSELH = 0;                 // Configure other AN pins as digital I/O
  C1ON_bit = 0;               // Disable comparators
  C2ON_bit = 0;
  
  TRISA  = 0xFF;              // PORTA is input
  TRISC  = 0;                 // PORTC is output
  TRISB  = 0;                 // PORTB is output

  do {
    temp_res = ADC_Read(2);   // Get 10-bit results of AD conversion
    PORTB = temp_res;         // Send lower 8 bits to PORTB
    PORTC = temp_res >> 8;    // Send 2 most significant bits to RC1, RC0
  } while(1);
}

HW Connection