'  Name    : pwm_generator.BAS                                   
'  Author  : Christopher Good                    
'  Notice  : Copyright (c) 2013                                
'          : All Rights Reserved                               
'  Date    : 2/4/2013                                          
'  Version : 1.0                                               
'  Notes   : Free source code. Compile with Proton IDE Lite (also free).  Program your PIC with IC-Prog (also free).                                            
' 
'          Pin8 = Ground                  - tie to common, connect to pin 1 via .1MF cap 
'          Pin7 = GPIO.0  - i/o           - LED #1 - flash0
'          Pin6 = GPIO.1  - i/o           - LED #2 - flash1
'          Pin5 = GPIO.2  - i/o           - PWM out - 1 to 2 ms
'          Pin4 = GPIO.3  - input only    - Switch down
'          Pin3 = GPIO.4  - i/o           - Switch up
'          Pin2 = GPIO.5  - i/o           - Switch display
'          Pin1 = Vcc                     - tie to +5v, connect to pin 8 via .1MF cap


Device 12C508
Config INTRC_OSC, MCLRE_OFF, WDT_OFF, CP_OFF                           ' set config fuses
OPTION_REG.5 = 0                                                       ' clock source internal

Dim Pulselen        As Byte                                            ' Pulselen can be 0 - 255, 100 = 1 ms, 200 = 2 ms
Dim Value10         As Byte
dim Value1          as byte
dim i               as byte

Pulselen = 50                                                           ' 100 is added later; default = 150 = 1.5 ms

Loop:
   input gpio.4
   If gpio.4 = 1 and pulselen < 100 Then
      Pulselen = Pulselen + 1
      GoSub flash0
   EndIf
   
   input gpio.3
   If gpio.3 = 1 and pulselen > 0 Then
      Pulselen = Pulselen - 1
      GoSub flash1
   EndIf
  
   input gpio.5
   If gpio.5 = 1 Then
       Value10 = Pulselen / 10
       Value1 = pulselen - (value10 * 10)
       
       if value10 > 0 then
         for i = 1 to value10
           gosub flash0
         next i
       endif
       
       if value1 > 0 then
         for i = 1 to value1
           gosub flash1
         next i
       endif
   endif
         
   PulsOut GPIO.2, 100 + Pulselen, High
   
   DelayMS 15
   
   GoTo Loop       
          
flash0:
   high GPIO.0
   DelayMS 125
   low GPIO.0
   delayms 125
   Return
   
flash1:
   high GPIO.1
   DelayMS 125
   low GPIO.1
   delayms 125
   Return