' PWM output wrapper class

' Copyright (C)2018-2023, Philip Munts dba Munts Technologies.
'
' Redistribution and use in source and binary forms, with or without
' modification, are permitted provided that the following conditions are met:
'
' * Redistributions of source code must retain the above copyright notice,
'   this list of conditions and the following disclaimer.
'
' THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
' IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
' ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
' LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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' SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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class PWM_Output
  var myperiod = -1
  var myfd     = -1

  ' freq : PWM pulse frequency in Hz
  ' duty : PWM output duty cycle in percent

  def Open(chip, channel, freq, duty)
    myperiod = 1000000000/freq
    ontime = round(duty/100.0*myperiod)
    myfd = libsimpleio.pwm_open(chip, channel, myperiod, ontime)
  enddef

  def Close()
    libsimpleio.pwm_close(myfd)
    myperiod = -1
    myfd     = -1
  enddef

  ' duty : PWM output duty cycle in percent

  def Write(duty)
    ontime = round(duty/100.0*myperiod)
    libsimpleio.pwm_write(myfd, ontime)
  enddef
endclass