'{$STAMP BS1}
' ***********************************************************************
' *                               <FLEX>                                *
' *             Source code for Basic Stamp 1 microcontrollers          *
' *          used for pwm controll of softshift solenoids on bows       *
' *                      by Dr.Godfried-Willem Raes                     *
' *                        Filename: FLEX_PWM.BS1                       *
' ***********************************************************************
' 29.10.1995: Note:
'             BSLOAD must run under DOS, not in a dos Window under WFWIN!!!
' 26.01.2003: Code written. We need 4 BS1's
' 27.01.2003: PC board takes 4 16C56 PICS. We do not use the SMD stamp, but
'             build it from discrete components.
 
' They accept 1 nibble data input through their pins 0-3, and output pwm-signals
' from their pin 7's. Resolution is <= 4 bits.
' Pin 7 may be connected to an RC-circuit, for integration:
'              4.7kOhm- 0.47mF gives 2.2 ms RC time   Icmax=1mA
'              10kOhm - 470nF                         Used in <DIANA>, 1995
'              10kOhm - 1 mF gives 10ms RC-time
'              10kOhm - 10mF gives an 0.1s RC-time    Icmax=0.5mA
'             100kOhm - 1 mF gives the same result.   Icmax=50microamps
' The dc-signal should be buffered. The DC range is 0-5V
      


' CODE-LIST:                    ' timing ' comments
'                               ' 0.5ms/instruction
Init:
        dirs = %10000000
' same as:
      '  input 0                 ' 1ms    ' input pin data bit 0
      '  input 1                 '        ' input pin data bit 1
      '  input 2                 ' 	 ' input pin data bit 2
      '  input 3                 ' 	 ' input pin data bit 3
      '  input 4                 '        ' nc
      '  input 5                 ' 1ms    ' nc  
      '  input 6                 ' 1ms    ' nc
      '  output 7                 ' 1ms    ' pwm output pin , for drift reduction we could also make it input.
        input 7 


Begin:
	b2 = pins                 
	b2 = b2 & %00001111     ' isolate low nibble
        if b2 = 0 then SolOff 
        if b2 = 15 then SolMax
        b2 = b2 + 1 * 16 - 1            ' add 1 and rotate left 4 bits , so now we have 2 - 256
	pwm 7,b2, 10             ' send out 1 - 255, do PWM for 10 periods.
        goto Begin

SolOff:
                         'output 7
        low 7            'out7, 0
        goto Begin

SolMax:
                         'output 7
        high 7           'out7, 1
        goto Begin  


bsave				' creates an OBJ file to disk