text: #!/usr/bin/env python3
  
  # Copyright (c) 2019-2020, NVIDIA CORPORATION. All rights reserved.
  # Copyright (c) 2021, Texas Instruments Incorporated. All rights reserved.
  # Permission is hereby granted, free of charge, to any person obtaining a
  # copy of this software and associated documentation files (the "Software"),
  # to deal in the Software without restriction, including without limitation
  # the rights to use, copy, modify, merge, publish, distribute, sublicense,
  # and/or sell copies of the Software, and to permit persons to whom the
  # Software is furnished to do so, subject to the following conditions:
  #
  # The above copyright notice and this permission notice shall be included in
  # all copies or substantial portions of the Software.
  #
  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  # THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  # DEALINGS IN THE SOFTWARE.
  
  import RPi.GPIO as GPIO
  import time
  
  all_pwm_pins = {
      'J721E_SK': {
          'sw_pwm': [11, 12, 15, 16], # Can be any valid GPIO pins
          'hw_pwm': [29, 31, 32, 33]  # Designated HW PWM pins
          },
  }
  
  pin_data = all_pwm_pins.get(GPIO.model)
  
  pwm_pins = pin_data['sw_pwm'] + pin_data['hw_pwm']
  
  def main():
      for pin in pwm_pins:
          print("Testing pin %d as PWM" % pin)
  
          # Board pin-numbering scheme
          GPIO.setmode(GPIO.BOARD)
          # set pin as an output pin with optional initial state of HIGH
          GPIO.setup(pin, GPIO.OUT, initial=GPIO.HIGH)
          p = GPIO.PWM(pin, 50)
          val = 25
          incr = 5
          p.start(val)
  
          try:
              cnt = 0
              while cnt < 10:
                  cnt += 1
                  time.sleep(0.25)
                  if val >= 100:
                      incr = -incr
                  if val <= 0:
                      incr = -incr
                  val += incr
                  p.ChangeDutyCycle(val)
          except KeyboardInterrupt:
              pass
          finally:
              pass
  
          p.stop()
          GPIO.cleanup()
  
  if __name__ == '__main__':
      main()
  