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ADC Library

ADC Library

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

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. See ADC_Init.
  • 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

 

 

Example Code

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

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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