microcontroller 2

DC motor and Fan speed control using Pic16f877 Microcontroller using PWM(Pulse width modulation) Technique

Pic microcontroller speed control project requirements

• Pic16f877 microcontroller
• L293d h-bridge Motor driver Ic
• DC Motor or small fan
• Crystal 20MHz
• Push Buttons
• connecting wires
• Bread board or PCB
• Power Supply battery

Project Code

#include< htc.h>
#include< pic.h>
#define _XTAL_FREQ   20000000 
void rundutycycle(unsigned int x );
#define s1           RA0
#define s2           RA1
#define s3           RA2
#define s4           RA3
#define s5           RA4
#define s6           RA5
void main()
{
ADCON1=0x06;             //All pins as digital
        TRISA=0b111111;          //PortA as Input
        TRISC2  = 0;             //Make CCP1 pin as output
CCP1CON = 0x0C;          //Configure CCP1 module in PWM mode
PR2   = 0xFF;            //Configure the Timer2 period
rundutycycle(512);
}

void rundutycycle(unsigned int dutycyc){
T2CON = 0x01;           // Set Prescaler to be 4, hence PWM frequency is set to 4.88KHz.
T2CON |= 0x04;          // Enable the Timer2, hence enable the PWM.

while(1){
CCPR1L   = dutycyc>>2;                // Put MSB 8 bits in CCPR1L
CCP1CON &= 0xCF;                 // Make bit4 and 5 zero
CCP1CON |= (0x30&(dutycyc<<4));         // Assign Last 2 LSBs to CCP1CON
if(s1==1){dutycyc=172; }
if(s2==1){dutycyc=342; }
if(s3==1){dutycyc=512; }
if(s4==1){dutycyc=686; }
if(s5==1){dutycyc=858; }
if(s6==1){dutycyc=1020; }
dutycyc=dutycyc;
}
}