Add step counter to IMU API

[Gregox273]

Enables the step counter in the BMI270, exposing a step_counter_read method as part of the IMU API.

Example usage:

import app
import imu

from events.input import Buttons, BUTTON_TYPES


class ExampleApp(app.App):
    def __init__(self):
        self.button_states = Buttons(self)
        self.acc_read = None
        self.steps_read = None

    def update(self, delta):
        if self.button_states.get(BUTTON_TYPES["CANCEL"]):
            self.button_states.clear()
            self.minimise()
        else:
            self.steps_read = imu.step_counter_read()

    def draw(self, ctx):
        ctx.save()
        ctx.rgb(0.2,0,0).rectangle(-120,-120,240,240).fill()
        if self.steps_read:
            ctx.rgb(1,0,0).move_to(-80,-40).text("steps:\n{}\n".format(self.steps_read))
        else:
            ctx.rgb(1,0,0).move_to(-80,0).text("no readings yet")
        ctx.restore()

__app_export__ = ExampleApp

[ChrisDick]

Thanks for this, it was on my to do list. I've given this a try and it is working for me. Can you add a stub for the sim in sim/fakes/imu.py, then I'll merge it.

[ChrisDick]

I've created a branch for the doc update using your example.

[MatthewWilkes]

Thank you for this, @Gregox273! I've added a simple stub to the simulator and merged this.