Lesson nr.10-Software PWM & RGB LED

Hardware setup:
This time we will implement software PWM mode, to control the light intensity of an RGB Led (Red Green Blue, which represents a pixel) .PORT RA0~RA2 and PORT RB0~RB2 will be used for this experiment.
Port B is used, to see more easier transitions between RBG colors.



Circuit Diagram:
For those who want to build it on their own breadboard or other platform, here is the electronic scheme built in Eagle Cad, free version:

Software:
Here is the C program written for MikroC PRO for PIC 2010 (version v4.15).

/*
'*******************************************************************************
'  Lesson nr.10:
'          Software PWM & RGB LED
'  Written by:
'          Aureliu Raducu Macovei, 2010.
'  Description:
'          In this experiment we will show how to implement software PWM to
'          control an RBG LED. PORT RA0~RA2 and PORT RB0~RB2 will be used for this experiment.
'  Test configuration:
'    MCU:                        PIC16F628A
'    Test.Board:                 WB-106 Breadboard 2420 dots
'    SW:                         MikroC PRO for PIC 2010 (version v4.15)
'  Configuration Word
'    Oscillator:                 INTOSC:I/O on RA.6, I/O on RA.7
'    Watchdog Timer:             OFF
'    Power up Timer:             Disabled
'    Master Clear Enable:        Enabled
'    Browun Out Detect:          Enabled
'    Low Voltage Program:        Disabled
'    Data EE Read Protect:       Disabled
'    Code Protect:               OFF
'*******************************************************************************
*/
// LED RGB module connections
sbit RED1 at RA0_bit;
sbit GREEN1 at RA1_bit;
sbit BLUE1 at RA2_bit;
sbit RED2 at RB0_bit;
sbit GREEN2 at RB1_bit;
sbit BLUE2 at RB2_bit;

sbit RED1_Direction at TRISA0_bit;
sbit GREEN1_Direction at TRISA1_bit;
sbit BLUE1_Direction at TRISA2_bit;
sbit RED2_Direction at TRISB0_bit;
sbit GREEN2_Direction at TRISB1_bit;
sbit BLUE2_Direction at TRISB2_bit;
// End LED RGB module connections

int i = 0 ,PWN_COUNTER = 256;

void PWM_FADE_0_TO_1(void);
void PWM_FADE_1_TO_0(void);
void Delay(int num);

void main(void)
{
 CMCON  |= 7;                     //  Comparator is Off
 TRISA = 0;
 PORTA = 0;
 TRISB = 0;
 PORTB = 0;

 while(1){
          PWM_FADE_0_TO_1();
          PWM_FADE_1_TO_0();
          }
}

void PWM_FADE_0_TO_1(void)        // Duty cycle -  0%  to  100%
{
 for (i = 0; i < PWN_COUNTER; i++)
 {
  RED1 = 0;
  RED2 = 0;
  Delay(PWN_COUNTER - i);
  RED1 = 1;
  RED2 = 1;
  Delay(i);
  }
 for (i = 0; i < PWN_COUNTER; i++)
 {
  GREEN1 = 0;
  GREEN2 = 0;
  Delay(PWN_COUNTER - i);
  GREEN1 = 1;
  GREEN2 = 1;
  Delay(i);
  }
 for (i = 0; i < PWN_COUNTER; i++)
 {
  BLUE1 = 0;
  BLUE2 = 0;
  Delay(PWN_COUNTER - i);
  BLUE1 = 1;
  BLUE2 = 1;
  Delay(i);
  }
}

void PWM_FADE_1_TO_0(void)         // Duty cycle -  100% to 0%
{
 for (i = 0; i < PWN_COUNTER; i++)
 {
  RED1 = 1;
  RED2 = 1;
  Delay(PWN_COUNTER - i);
  RED1 = 0;
  RED2 = 0;
  Delay(i);
  }
 for (i = 0; i < PWN_COUNTER; i++)
 {
  GREEN1 = 1;
  GREEN2 = 1;
  Delay(PWN_COUNTER - i);
  GREEN1 = 0;
  GREEN2 = 0;
  Delay(i);
  }
 for (i = 0; i < PWN_COUNTER; i++)
 {
  BLUE1 = 1;
  BLUE2 = 1;
  Delay(PWN_COUNTER - i);
  BLUE1 = 0;
  BLUE2 = 0;
  Delay(i);
  }
}

void Delay(int num)
{
 while(num>0)
 num--;
}