'  Name    : Switch_Output.BAS                                   
'  Author  : Christopher Good                    
'  Notice  : Copyright (c) 2021                                
'          : All Rights Reserved                               
'  Date    : 7/21/2021                                          
'  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           - output - 0 to 40 ms on, invert of that off = (0/25/50/75/100 % duty cyle) -> use RC filter to convert to analog signal (0/1.25/2.5/3.75/5 V)
'          Pin6 = GPIO.1  - i/o           - Switch 1 = 0%
'          Pin5 = GPIO.2  - i/o           - Switch 2 = 25%
'          Pin4 = GPIO.3  - input only    - Switch 3 = 50%
'          Pin3 = GPIO.4  - i/o           - Switch 4 = 75%
'          Pin2 = GPIO.5  - i/o           - Switch 5 = 100%
'          Pin1 = Vcc                     - tie to +5v, connect to pin 8 via .1MF cap
'
'    RC filter selection: R=21K Ohms, C=10 uF --> Tau (time constant) = .21 seconds

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

Dim OnTime As Byte
Dim OffTime as byte
Ontime = 0            'default to 0% duty cycle
xtal = 4              'tell compiler the internal oscillator runs at 4 MHz, this is used for the DelayMS command

trisio = %111110

Loop:                 'loop time = ~40 ms
   
   ' if a switch if pressed, set the OnTime duty cycle in ms (if more than one switch is pressed, higher GPIO.x has precedence)
   if GPIO.1 = 1 then OnTime = 0        ' 0% duty cycle 
   if GPIO.2 = 1 then OnTime = 10       ' 25% duty cycle
   if Gpio.3 = 1 then OnTime = 20       ' 50% duty cycle
   if Gpio.4 = 1 then OnTime = 30       ' 75% duty cylce 
   if gpio.5 = 1 then OnTime = 40       ' 100% duty cycle    
   
   offtime = 40 - ontime                'OffTime is invert of OnTime                    
    
   ' if the duty cycle is <> 0% (i.e. if the output is ever on at all), set the output high and wait for the OnTime
   if Ontime <> 0 then 
     high GPIO.0
     Delayms ontime
   endif
     
   ' if the duty cycle is <> 100% (i.e. if the output is ever off at all), set the output low and wait for the OffTime
   if offtime <> 0 Then
     Low GPIO.0
     Delayms Offtime
   endif 

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