The microcontroller PIC16F877A has 8 ADC (Analog to Digital Converter) channels. The resolution of the PIC16F877A ADC is 10-bit, which means the analog value after conversion is stored as a 10-bit number that varies from 0 to 1023 (0x3FF). The A/D module has high and low-voltage reference input that is software selectable to some combination of VDD, VSS, RA2 or RA3.
PIC16F877A ADC example with CCS C:
This is an example to start with the ADC module, example circuit schematic is shown below:
The reference voltage is set to VDD (+5V) and GND.
To know how to use LCD display with PIC16F877A microcontroller see the following topic:
Interfacing PIC16F877A with LCD using CCS C compiler
PIC16F877A ADC example CCS C code:
This is the C code used for this example with some comments.
// PIC16F877A ADC example with CCS C compiler
// http://ccspicc.blogspot.com/
// electronnote@gmail.com
//LCD module connections
#define LCD_RS_PIN PIN_C0
#define LCD_RW_PIN PIN_C1
#define LCD_ENABLE_PIN PIN_C2
#define LCD_DATA4 PIN_C3
#define LCD_DATA5 PIN_C4
#define LCD_DATA6 PIN_C5
#define LCD_DATA7 PIN_C6
//End LCD module connections
#include <16F877A.h>
#device ADC=10
#use delay(crystal=8000000)
#include <lcd.c>
unsigned int16 i;
void main(){
lcd_init(); // Initialize LCD module
setup_adc(ADC_CLOCK_DIV_32); // Set ADC conversion time to 32Tosc
setup_adc_ports(AN0); // Configure AN0 as analog
set_adc_channel(0); // Select channel 0 input
delay_ms(100); // Wait 100ms
lcd_gotoxy(3, 1); // Go to column 3 row 1
lcd_putc("ADC reading:");
while(TRUE){
i = read_adc();
lcd_gotoxy(7, 2); // Go to column 7 row 2
printf(lcd_putc,"%4Lu",i); // Write i with 4 numbers max
delay_ms(10); // Wait 10ms
}
}
PIC16F877A ADC example video:
The following video shows our example in a real hardware circuit.
