120 lines
3.0 KiB
Rust
120 lines
3.0 KiB
Rust
// src/send.rs
|
|
|
|
use embassy_stm32::gpio::{Level, Output};
|
|
use embassy_sync::{
|
|
blocking_mutex::raw::CriticalSectionRawMutex,
|
|
channel::{Receiver, Sender},
|
|
};
|
|
use embassy_time::{Duration, Ticker};
|
|
|
|
use crate::{level_for_bit, Encoding};
|
|
|
|
const START: u8 = 0x7E;
|
|
const STOP: u8 = 0x81;
|
|
const BIT_PERIOD: Duration = Duration::from_millis(10);
|
|
|
|
pub type Tx = Sender<'static, CriticalSectionRawMutex, u8, 128>;
|
|
|
|
fn set_level(pin: &mut Output<'static>, is_high: bool) {
|
|
pin.set_level(if is_high { Level::High } else { Level::Low });
|
|
}
|
|
|
|
async fn send_byte(byte: u8, tx: &Tx) {
|
|
for i in (0..8).rev() {
|
|
tx.send((byte >> i) & 1).await;
|
|
}
|
|
}
|
|
|
|
/// [START] [LEN] [PAYLOAD ...] [CRC] [P] [STOP]
|
|
pub async fn msg_encode(payload: &[u8], tx: &Tx) {
|
|
// start
|
|
send_byte(START, tx).await;
|
|
|
|
// len
|
|
let len = payload.len() as u8;
|
|
send_byte(len, tx).await;
|
|
for &b in payload {
|
|
send_byte(b, tx).await;
|
|
}
|
|
|
|
// crc
|
|
let mut crc = crc8(0, len);
|
|
for &b in payload {
|
|
crc = crc8(crc, b);
|
|
}
|
|
send_byte(crc, tx).await;
|
|
|
|
let mut ones = len.count_ones() + crc.count_ones();
|
|
for &b in payload {
|
|
ones += b.count_ones();
|
|
}
|
|
tx.send((ones as u8) & 1).await;
|
|
|
|
send_byte(STOP, tx).await;
|
|
|
|
// idle
|
|
tx.send(1).await;
|
|
}
|
|
|
|
fn crc8(crc: u8, byte: u8) -> u8 {
|
|
let mut c = crc ^ byte;
|
|
for _ in 0..8 {
|
|
c = if c & 0x80 != 0 {
|
|
(c << 1) ^ 0x07
|
|
} else {
|
|
c << 1
|
|
};
|
|
}
|
|
c
|
|
}
|
|
|
|
#[embassy_executor::task]
|
|
pub async fn bit_send(
|
|
mut pin: Output<'static>,
|
|
rx: Receiver<'static, CriticalSectionRawMutex, u8, 128>,
|
|
encoding: Encoding,
|
|
) {
|
|
let mut ticker = Ticker::every(BIT_PERIOD / 2);
|
|
let mut is_high = level_for_bit(1);
|
|
set_level(&mut pin, is_high);
|
|
|
|
loop {
|
|
let bit = rx.receive().await;
|
|
match encoding {
|
|
Encoding::Nrz => {
|
|
is_high = level_for_bit(bit);
|
|
set_level(&mut pin, is_high);
|
|
ticker.next().await;
|
|
}
|
|
// toggle, ak sme v 1, inac sa nedeje nic
|
|
Encoding::Nrzi => {
|
|
if bit == 1 {
|
|
is_high = !is_high;
|
|
if is_high {
|
|
pin.set_high();
|
|
} else {
|
|
pin.set_low();
|
|
}
|
|
}
|
|
ticker.next().await;
|
|
}
|
|
// manchester xor tabulka
|
|
Encoding::Manchester => {
|
|
if bit == 1 {
|
|
// high -> low
|
|
set_level(&mut pin, level_for_bit(1));
|
|
ticker.next().await;
|
|
set_level(&mut pin, level_for_bit(0));
|
|
ticker.next().await;
|
|
} else {
|
|
// low -> high
|
|
set_level(&mut pin, level_for_bit(0));
|
|
ticker.next().await;
|
|
set_level(&mut pin, level_for_bit(1));
|
|
ticker.next().await;
|
|
}
|
|
}
|
|
};
|
|
}
|
|
}
|