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Remote Firmata Management

The methods in this section allow your application to perform some Firmata management functions remotely.

keep_alive

For Arduino's utilizing an ATmega328P processor, this exclusive FirmataExpress feature will reset the Arduino if serial communication is lost between pymata-express and the Arduino.

 async def keep_alive(self, period=1, margin=0.3)

    This is a FirmataExpress feature.

    Periodically send a keep alive message to the Arduino.

    If the Arduino does not received a keep alive, the Arduino will physically reset itself.

    Frequency of keep alive transmission is calculated as follows: 
        keep_alive_sent = period - margin

    :param period: Time period between keepalives.
                   Range is 0-10 seconds. 
                0 disables the keepalive mechanism.

    :param margin: Safety margin to assure keepalives are 
                   sent before period expires. Range is 0.1 to 0.9

Example:

keep_alive.py

Notes:

When keep_alive is called, it spawns and runs in its own thread.

send_reset

 async def send_reset(self)

    Send a Sysex reset command to the arduino

Examples:

All examples call shutdown, which in turn calls send_reset.

Notes:

This command will reset several Firmata internal data structures.

  • It resets its internal i2c flags to indicate there are no i2c devices present.
  • Digital reporting is turned off.
  • It resets any analog pin that was set to a digital mode back to analog mode.
  • If a pin was configured for tone, the tone is turned off.
  • It clears all servo entries from its servo map.
  • It sets the number of active sonar devices to zero.

The shutdown method calls send_reset.

shutdown

  async def shutdown(self)

    This method attempts an orderly shutdown. 
    If any exceptions are thrown, they are ignored.

Examples:

All the examples call shutdown.



Copyright (C) 2020 Alan Yorinks. All Rights Reserved.