Mydin-advanced-usage

Abstract

Before going into the details of the various controlers and backplanes, it may be opportune to learn some advanced behaviors of the MyDin asyncio implementation.

RUN_APP

RUN_APP pin is used to stop the MyDin software stack (or script execution after a reboot).

It is a convenient way to recover the control on the module when script goes wrong. It would also offer the full access to REPL.

When setting the RUN_APP pin to the "Stop" position (so tied to ground) while the MyDin software is already running, the code may takes up to 3 seconds to terminates.

It is also a good practice to check the RUN_APP pin in the boot.py startup file. This may allows debugging operations when Network operation goes wrong!

from machine import Pin
# Use the RUN_APP pin as defined on your controler board!
RUN_APP = Pin.board.GP3  # High=Run, Low=Stop

if Pin( RUN_APP, Pin.IN, Pin.PULL_UP ).value()==False:
  print( '[BOOT] skip execution (RUN_APP is false)' )
else:
  print( '[BOOT] entering...' )
  # >>> PLACE BOOT CODE HERE <<<
  print( '[BOOT] exit' )

Exception handling

An exception occuring in the userloop task will be captured and will ends the code execution.

Exception occuring in other tasks will be only be reported into REPL.