touchpad.rs

use core::convert::Infallible;
use embedded_hal::{
    blocking::{delay::DelayMs, i2c::WriteRead},
    digital::v2::OutputPin,
};
use rp2040_hal::Timer;
use rtt_target::rprintln;

const ADDRESS: u8 = 0x3B;

pub enum Registers {
    Motion = 0x02,
    DeltaX = 0x03,
    DeltaY = 0x04,
}

pub struct Touchpad<I: WriteRead, R: OutputPin, S: OutputPin> {
    i2c: I,
    reset: R,
    shutdown: S,
}

impl<I: WriteRead, R: OutputPin<Error = Infallible>, S: OutputPin<Error = Infallible>>
    Touchpad<I, R, S>
{
    // TODO can take a reference to a timer
    pub fn new(i2c: I, mut reset: R, mut shutdown: S, mut timer: Timer) -> Self {
        shutdown.set_low().unwrap();
        reset.set_low().unwrap();
        timer.delay_ms(100);
        reset.set_high().unwrap();

        Self {
            i2c,
            reset,
            shutdown,
        }
    }

    pub fn get_delta_motion(&mut self) -> Result<(i8, i8), I::Error> {
        let mut x = [0];
        self.i2c
            .write_read(ADDRESS, &[Registers::DeltaX as u8], &mut x)?;
        let x = x[0];

        let mut y = [0];
        self.i2c
            .write_read(ADDRESS, &[Registers::DeltaY as u8], &mut y)?;
        let y = y[0];

        let x = if x < 128 {
            x.try_into().unwrap()
        } else {
            i8::try_from(i16::from(x) - 256).unwrap()
        };

        let y = if y < 128 {
            y.try_into().unwrap()
        } else {
            i8::try_from(i16::from(y) - 256).unwrap()
        };

        Ok((x, y))
    }
}