embedded-hal async driver for dot matrix lcd display

lcd is reset and initialized with display: off, it's off just because it's like that in reset procedure,

even if it seems to work with display: on

currently only works in write-only mode

use dummy pin for RW pin

doesn't track the current position

this is because this driver is designed to have very small memory footprint

the type Lcd can be zero sized depending on pin type and delay type

you should use seek to change line and position

currently blocking io and full width bus isn't supported

(it shouldn't be "hard") i'm just lazy

rw pin will allow use of busy flag but it isn't implemented

instead, this driver works by waiting for a while

waiting time is longer than the one in the spec, this is because i found problem with my compatible chip(eg. ks0066)

without rw pin support

example

pub struct EmbassyDelayNs;

impl DelayNs for EmbassyDelayNs {
    async fn delay_ns(&mut self, ns: u32) {
        embassy_time::Timer::after_micros(ns.div_ceil(1000) as u64).await;
    }
}
    let mut lcd = Lcd::<_, _, _, _, Infallible>::new(
        LcdPinConfiguration {
            en: pins.d7.into_output(),
            rs: pins.d6.into_output(),
            bus: HalfWidthBus {
                d4: pins.d8.into_output(),
                d5: pins.d9.into_output(),
                d6: pins.d10.into_output(),
                d7: pins.d11.into_output()
            }
        },
        EmbassyDelayNs,
        Lines::TwoLines,
        EntryMode::default()
    ).await.unwrap();

    lcd.set_display_control(DisplayControl::default()).await.unwrap();
    lcd.seek(SeekFrom::Start(0)).await.unwrap(); //first line address 0..16
    lcd.write_all("first line".as_bytes()).await.unwrap();
    lcd.seek(SeekFrom::Start(40)).await.unwrap(); //second line address 40..56
    lcd.write_all("second line".as_bytes()).await.unwrap();