Crate ask433

ask433

A portable, no_std Rust driver for Amplitude Shift Keying (ASK/OOK) 433 MHz RF transceivers, compatible with cheap modules like the FS1000A and XY-MK-5V.

This driver implements a software-based ASK modem using:

• embedded-hal traits for digital I/O and timing
• a software PLL for reception and demodulation
• interrupt-safe buffer access with critical-section
• optional tick sources using either timer interrupts or blocking delay

Crate features

Feature	Description
std	Disables #![no_std] support and replaces healpess::Vecs with
std::vec::Vecs
delay-loop	Uses embedded_hal::blocking::delay::DelayUs for bit timing
timer-isr (default)	Uses critical_section::with for bit timing
defmt	Uses defmt logging
log	Uses log logging

Software Features

• Transmitter and receiver in pure software (no UART or DMA)
• Bit-level protocol compatible with RadioHead RH_ASK
• Supports training preamble, 4b6b encoding, and CRC16 validation
• Fully portable across AVR (e.g., Arduino Uno) and ARM Cortex-M targets
• Feature flags for interrupt-driven or blocking tick scheduling

Usage

use ask433::driver::AskDriver;
fn main() {
    // ...
    let mut driver: AskDriver<Pin, Pin, Pin> = AskDriver::new(tx_pin, rx_pin, None, 8, None, None);
                                                       // ^ this is the number of interrupts per bit
    loop {
        driver.tick(); // Call at ~62.5 µs intervals
    }
}

Or, use run_tick_loop() with a DelayUs implementation:

use ask433::driver::AskDriver;
#[cfg(feature = "delay-loop")]
use ask433::timer::run_ask_tick_loop;

fn main() {
    // ...
    let mut driver: AskDriver<Pin, Pin, Pin> = AskDriver::new(tx_pin, rx_pin, None, 8, None, None);
    run_ask_tick_loop(&mut driver, &mut delay, 63);
}

Feature Flags

• timer-isr: Use a hardware timer ISR to call tick() (requires platform-specific ISR setup)
• delay-loop: Use a blocking loop to drive tick() with embedded_hal::blocking::delay::DelayUs

Integration Notes

• Transmit and receive timing are based on ~2 kbps bit rate (~62.5 µs per tick)
• Timing precision is critical; hardware timer configuration is recommended for reliability
• Only one driver instance should be active at a time in interrupt-driven mode

Status

This crate is in early development. Contributions welcome!

– Designed for #![no_std] use in resource-constrained embedded environments.

Re-exports

pub use critical_section;

pub use heapless;

Modules

consts

Constants used across the ASK protocol implementation.

driver

ASK/OOK modem driver for 433 MHz RF transceivers.

encoding

4b6b symbol encoding and decoding for ASK/OOK message framing.

pll

Software PLL for ASK/OOK signal demodulation.

timer

Timer and tick-loop utilities for ASK driver.

Macros

init_ask_driver

Declares a static global ASK_DRIVER instance protected by a critical_section mutex.

receive_from_ask

Attempts to receive a completed message from the global ASK driver instance.

send_from_ask

Sends a message from the global ASK driver using a heapless Vec<u8>.

setup_ask_driver

Initializes the global ASK_DRIVER singleton with a new driver instance.

tick_ask_timer

Calls tick() on the global ASK_DRIVER if it has been initialized.