Dev/event handler

[jo-bru]

This version of the controller firmware is not complete yet, as discussed. This version includes the following changes/implementations:

To be able to handle different sorts of feedback messages, a ResponseCode field with the following options was included:

• DEBUG: used only for debugging purpose

• ERROR: used for error handling

• ACK: used for acknowledging actions that are not finished yet (used for non-blocking/event-driven mode)

• DONE: used for giving feedback on finished actions

• DATA: used for returning data to the gateway

For handling actions and events on the gateway, the following ProfileStates are used to indicate the state of each profile:

• UNREG: the profile is created, but not yet registered on the MCU

• IDLE: the profile is registered and available for further requests

• WAIT: the profile is waiting for an ACK (blocking state: if a profile is in the WAIT state all profiles of the same MCU are blocked)

• BUSY: the profile is waiting for a DONE/DATA (non-blocking state: other profiles are not blocked)

To manage all profile registered on the MCU, the profile_manager.cpp sub-module was added (#7):

• in the registered_profiles[255] are all registered profiles saved to retrieve information for each profile

• an existing profile gets simply overwritten

• for now, the deletion of profiles is not supported

• every successful registration is acknowledged with a DONE feedback message

The following drivers were added/completed (#9):

• digital_generic: functions for reading a digital pin in blocking and non-blocking (event-driven) mode were added

• color_sensor: for now, the IIC address of the device is hardcoded, therefore only one color sensor can be used at the same time

• ultrasonic_sensor: for now, the measurement is hardcoded (only for testing, as I have no ultrasonic sensor at home)

• step_lowlevel: not implemented yet (only skeleton created with the automatic driver initialization)

To test the firmware, the following tests were added to the simple_gateway.py file:

• Updating profiles: overwrite profile 2 every 5 loops the change LED color (green <=> blue)

• Event handling: create a profile for button A and listen for an event (read_event_digital())

• Color sensor: get the current measurement of the sensor (only working if the sensor is connected to IIC port => !! wrong label on controller backside: use Digital ports for IIC)

• Ultrasonic sensor: get a measurement of the sensor (result is hardcoded as explained before)

The event_handler() was added to handle non-blocking requests (#5 ):

• each driver that should support non-blocking requests needs an event_driver_name function (e.g. event_digital_generic())

The automatic driver initialization script is completed (#8):

• when running the script as described in the README file, all needed code sections are automatically filled in marked with TODO where manual implementation is needed

[jo-bru]

I've changed all the discussed parts and updated the FSM, which I added to the README file. I've run a simple test (subroutine_test()) with the uArm robot at home (see GIF).

Since the belt conveyor and the slider are too big to easily take home, I could not implement the step_lowlevel driver yet. For now, I haven't implemented the non-volatile backup mechanism yet as it is labeled as an optional issue (see issue #3).

The firmware should be ready to use with further gateway implementations IMO. We may have to optimize the firmware in the future to reduce the latency.

[iomz]

@jo-bru Wonderful, thank you! I'll review the changes this afternoon. Let's discuss the gRPC gateway tomorrow.