Examples

Here are example use cases for GPIOManager, PWMManager, and I2CManager.

GPIOManager Examples

• Basic GPIO Input Pin Setup with Callback:

  import gpio_manager
  import time
  
  def button_pressed_callback():
      print("Button was pressed on pin 17")
  
  # Set up GPIO Manager
  gpio = gpio_manager.GPIOManager()
  
  # Configure pin 17 as input with a pull-up resistor
  gpio.add_input_pin(17, pull_resistor_state=gpio_manager.InternPullResistorState.PULLUP)
  
  # Assign callback to the pin for falling edge detection
  gpio.assign_callback(17, button_pressed_callback, trigger_edge=gpio_manager.TriggerEdge.FALLING)
  
  while True:
      time.sleep(1)
      pass
  

• GPIO Output Pin Setup and State Change:

  import gpio_manager
  import time
  # Set up GPIO Manager
  gpio = gpio_manager.GPIOManager()
  
  # Configure pin 18 as an output pin with an initial LOW state
  gpio.add_output_pin(18, pin_state=gpio_manager.PinState.LOW)
  
  # Set pin 18 to HIGH
  gpio.set_output_pin(18, gpio_manager.PinState.HIGH)
  time.sleep(2)
  gpio.cleanup()
  

PWMManager Examples

• PWM Setup and Basic LED Brightness Control:

  import gpio_manager
  
  # Set up PWM Manager
  pwm = gpio_manager.PWMManager()
  
  # Set up PWM on channel 0, 1000 Hz frequency, and 50% duty cycle
  pwm.setup_pwm_channel(0, frequency_hz=1000, duty_cycle=50)
  
  # Start PWM on channel 0
  pwm.start_pwm_channel(0)
  
  # Change duty cycle to 75%
  pwm.set_duty_cycle(0, 75)
  
  # Stop PWM on channel 0
  pwm.stop_pwm_channel(0)
  

• RGB LED with PWM Control:

  import gpio_manager
  import time
  
  # Set up PWM Manager
  pwm = gpio_manager.PWMManager()
  
  # Set up RGB LED pins with PWM (channels 0 and 1)
  pwm.setup_pwm_channel(0, frequency_hz=1000)
  pwm.setup_pwm_channel(1, frequency_hz=1000)
  
  # Function to cycle RGB colors
  def cycle_rgb():
      for duty_cycle in range(0, 101, 5):
          pwm.set_duty_cycle(0, duty_cycle)  # Red
          pwm.set_duty_cycle(1, 100 - duty_cycle)  # Green
          time.sleep(0.05)
  
  # Start PWM on channels 0 and 1
  pwm.start_pwm_channel(0)
  pwm.start_pwm_channel(1)
  
  # Cycle through colors
  cycle_rgb()
  
  # Stop PWM on all channels
  pwm.cleanup()
  

• Servo motor control on PWM channel 0 (gpio pin 18):

  import gpio_manager
  
  Period_ms = 20
  PWM_CHANNEL = 0
  default_pulse_width = 1.5
  max_rotation = 90
  
  
  def setup_gpio():
      pwm = gpio_manager.PWMManager()
      pwm.setup_pwm_channel(PWM_CHANNEL, period_ms=Period_ms, pulse_width_ms=default_pulse_width)
      pwm.start_pwm_channel(PWM_CHANNEL)
  
  
  def degrees_to_pulse_with(degrees):
      if degrees < -max_rotation or degrees > max_rotation:
          raise ValueError("Angle must be between -90 and 90 degrees.")
  
      # Mapping -90 degrees to 0.5 ms and 90 degrees to 2.5 ms
      max_pulse = 2.5  # Pulse width for 90 degrees
      neutral_pulse = 1.5  # Pulse width for 0 degrees
  
      # Slope of the linear equation
      pulse_width = neutral_pulse + (-degrees / max_rotation) * (max_pulse - neutral_pulse)
  
      return pulse_width
  
  
  def get_user_input():
      while True:
          val = input("Please enter an angle in degrees (-90 - 90) or exit to exit: ")
  
          if val.lower() == "exit":
              return None
  
          try:
              int_data = float(val)
              if -max_rotation <= int_data <= max_rotation:
                  return int_data
              else:
                  raise ValueError
          except ValueError:
              print("invalid value, please try again \n")
              continue
  
  
  def loop():
      pwm = gpio_manager.PWMManager()
      while True:
          user_input = get_user_input()
          if user_input is None:
              exit()
          pwm.set_pulse_width(PWM_CHANNEL, degrees_to_pulse_with(user_input))
  
  
  def main():
      try:
          setup_gpio()
          loop()
  
      except KeyboardInterrupt:
          print("\nCTRL-C detected.")
  
      finally:
          pwm = gpio_manager.PWMManager()
          pwm.cleanup()
          print("GPIO Port has been cleaned up.")
          print("**************** PROGRAM TERMINATED ****************")
          print()
  
  
  if __name__ == "__main__":
      main()
  

I2CManager Examples

• Basic I2C Communication:

  import gpio_manager
  
  # Set up I2C Manager
  i2c = gpio_manager.I2CManager()
  
  # Open I2C bus
  i2c.open(bus=1)
  
  # Write a byte to a slave device at address 0x20
  i2c.write_byte(0x20, 0xFF)
  
  # Read a byte from the slave device
  data = i2c.read_byte(0x20)
  print("Received byte:", data)
  
  # Close the I2C bus
  i2c.close()
  

• I2C Block Read and Write:

  import gpio_manager
  
  # Set up I2C Manager
  i2c = gpio_manager.I2CManager()
  
  # Open I2C bus
  i2c.open(bus=1)
  
  # Write a block of bytes with a command
  i2c.block_write(0x20, 0x01, b'\x01\x02\x03')
  
  # Read a block of data with a command
  data = i2c.block_read(0x20, 0x01, 3)
  print("Received block:", data)
  
  # Close the I2C bus
  i2c.close()