knob_task.h File Reference

The rotary knob's reader: an MT6701 at 0x06 on an I2C (Inter-Integrated Circuit) bus of its own (BOARD_KNOB_PIN_SDA, BOARD_KNOB_PIN_SCL), polled from a task of its own. More...

#include <stdbool.h>
#include <stdint.h>

Go to the source code of this file.

Functions
void	knob_task_attach (void)
	Set up the knob's bus and register the sensor on it.
void	knob_task_start (void)
void	knob_task_set_enabled (bool on)
int	knob_task_take (void)

Detailed Description

The rotary knob's reader: an MT6701 at 0x06 on an I2C (Inter-Integrated Circuit) bus of its own (BOARD_KNOB_PIN_SDA, BOARD_KNOB_PIN_SCL), polled from a task of its own.

The sensor is registered on the bus once, before the control task starts, and the task reads it only while the setting is on, so a panel with the knob off sends nothing to 0x06. While the knob has no reference the task probes 0x06 before reading, so a panel with the knob on and no sensor logs nothing per poll. What it hands over is motion, a count of steps since the last take, never an angle: a knob that stops answering stops adding to it.

SPDX-License-Identifier: MIT

Function Documentation

knob_task_attach()

void knob_task_attach

(

void

)

Set up the knob's bus and register the sensor on it.

Call once, before knob_task_start(). Sends nothing. A bus or a device that does not come up is logged; the task then reads nothing.

knob_task_set_enabled()

void knob_task_set_enabled

(

bool

on

)

Poll the sensor (true) or leave the bus alone (false).

knob_task_start()

void knob_task_start

(

void

)

Create the task. Call once, after knob_task_attach().

knob_task_take()

int knob_task_take

(

void

)

The steps turned since the last call, signed; clears the count.