5 releases

0.2.3 Apr 19, 2023
0.2.2 Dec 12, 2022
0.2.1 Dec 9, 2022
0.2.0 Dec 9, 2022
0.1.0 Dec 5, 2022

#408 in Embedded development

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MIT license

453 lines

Avr Boot

Rust License docs.rs

This crate contains functions to write to the program memory of Avr MCUs, using the spm instruction.

It could be considered a reimagining of the macros in boot.h from avr-libc. If you're looking to create a bootloader, this crate should be useful.

It is hal independent, and optimised for code size. Written in Rust plus some artisanal, hand-crafted asm.

This crate aims to support as many MCUs as possible, abstracting over their differences wherever practical.
Among the huge range of Avr MCUs, there are many variations on the self-programming process. It is essential you read the documentation for your target MCU carefully.
On many devices the spm instruction will only work if the programming code is in the bootloader section of the flash memory. On most MCUs the fuses will also need to be set correctly to allow self-programming. Interrupts should always be disabled while self-programming.

This crate supports regular and extended (>64k) addressing modes

Getting started

Add the module to your Cargo.toml:

avr-boot = "0.2.3"

Pick from the high level API:

use avr_boot::PageBuffer;

let address: u16 = 0x1000;
let data = [0xffff; PageBuffer::LEN];
let buff = PageBuffer::new(address);

Or the low level one:

use avr_boot::{spm, SPM_PAGESIZE_WORDS, Address};

let address: u16 = 0x1000;
for w in 0..SPM_PAGESIZE_WORDS {
    spm::fill_page((address + (w * 2) as u16), 0x1234);

Check out the examples module for more usage examples

Supported MCUs:

Physically tested with:

  • atmega328p
  • atmega644
  • attiny85

Simulated test using simavr:

atmega1280, atmega1281, atmega1284, atmega1284p, atmega128rfr2, atmega164p, atmega164pa, atmega168, atmega168p, atmega168pa, atmega2560, atmega2561, atmega324a, atmega324p, atmega324pa, atmega328, atmega328p, atmega48, atmega48p, atmega48pa, atmega644, atmega644p, atmega88, atmega88p, atmega88pa

Library will at least build for:

at90can128, at90can32, at90can64, at90pwm1, at90pwm161, at90pwm216, at90pwm2b, at90pwm316, at90pwm3b, at90pwm81, at90usb1286, at90usb1287, at90usb162, at90usb646, at90usb647, at90usb82, ata5272, ata5505, ata5782, ata5790, ata5790n, ata5791, ata5795, ata5831, ata6285, ata6286, ata6612c, ata6613c, ata6614q, ata6617c, ata664251, ata8210, ata8510, atmega128, atmega128a, atmega128rfa1, atmega16, atmega162, atmega164a, atmega165a, atmega165p, atmega165pa, atmega168a, atmega168pb, atmega169a, atmega169p, atmega169pa, atmega16a, atmega16hva, atmega16hvb, atmega16hvbrevb, atmega16m1, atmega16u2, atmega16u4, atmega2564rfr2, atmega256rfr2, atmega32, atmega324pb, atmega325, atmega3250, atmega3250a, atmega3250p, atmega3250pa, atmega325a, atmega325p, atmega325pa, atmega328pb, atmega329, atmega3290, atmega3290a, atmega3290p, atmega3290pa, atmega329a, atmega329p, atmega329pa, atmega32a, atmega32c1, atmega32hvb, atmega32hvbrevb, atmega32m1, atmega32u2, atmega32u4, atmega406, atmega48a, atmega48pb, atmega64, atmega640, atmega644a, atmega644pa, atmega644rfr2, atmega645, atmega6450, atmega6450a, atmega6450p, atmega645a, atmega645p, atmega649, atmega6490, atmega6490a, atmega6490p, atmega649a, atmega649p, atmega64a, atmega64c1, atmega64hve2, atmega64m1, atmega64rfr2, atmega8, atmega8515, atmega8535, atmega88a, atmega88pb, atmega8a, atmega8hva, atmega8u2, attiny13, attiny13a, attiny1634, attiny167, attiny2313, attiny2313a, attiny24, attiny24a, attiny25, attiny261, attiny261a, attiny4313, attiny43u, attiny44, attiny441, attiny44a, attiny45, attiny461, attiny461a, attiny48, attiny84, attiny841, attiny84a, attiny85, attiny861, attiny861a, attiny87, attiny88

However they are all missing support from either avr-hal or simavr, so I've not been able to test further.

Unsupported MCUs:

At the moment there is no support for chips that use the newer 'NVM' controller:

  • attiny10x, attiny10/20/40, attiny4/5/9
  • attiny8xx, attiny4xx, attiny16xx, attiny32xx, attiny2xx, attiny2xx
  • atmega80x, atmega48xx, atmega32xx, atmega16xx

And some MCUs don't support self-programming at all:

  • attiny10/12/15, attiny828


PRs welcome on github


~31K SLoC