DC motor interfacing with PIC16F877A
It is easy to control the speed of a DC motor using PIC16F877A microcontroller since this microcontroller has a CCP module to generate a PWM signal, and by varying the duty cycle of the PWM signal the power delivered to the motor will also vary which causes the speed to change. This topic shows how to make a DC motor speed controller using PIC16F877A where a potentiometer is used to control motor speed.If you need to see how to use potentiometer with PIC16F877A visit the following topic:
PIC16F877A ADC example with CCS PIC C compiler
If you need to see how to generate a PWM signal using PIC16F877A visit the following topic:
PIC16F877A PWM example with CCS PIC C compiler
DC Motor speed control with PIC16F877A circuit:
To control the speed of a DC motor only one transistor is needed, in this project an N-type mosfet is used as shown in the circuit schematic below:
PIC16F877A CCP1 module is used as PWM with a frequency of 500Hz.
DC Motor speed control with PIC16F877A CCS C code:
The code is described through its comments.
// DC motor speed control using PIC16F877A CCS C code
// http://ccspicc.blogspot.com/
// electronnote@gmail.com
#include <16F877A.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#device ADC = 10
#use delay(clock = 8000000)
unsigned int16 i ;
void main(){
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 AN0
setup_ccp1(CCP_PWM); // Configure CCP1 as a PWM
setup_timer_2(T2_DIV_BY_16, 250, 1); // Set PWM frequency to 500Hz
delay_ms(100); // Wait 100ms
while(TRUE){
i = read_adc(); // Read from AN0 and store in i
set_pwm1_duty(i); // PWM1 duty cycle set
delay_ms(10); // Wait 10ms
}
}
DC Motor speed control with PIC16F877A video:
The following video shows a hardware circuit for this project.