Crate avr_boot

Avr Boot

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, but in Rust, plus some artisanal, hand-crafted asm. If you’re looking to create a bootloader, this crate should be useful.

It is hal independent, and optimised for code size.

Regular and extended (>64k) addressing modes are supported.

Getting started

Add the module to your Cargo.toml:

[dependencies]
avr-boot = "0.1.0"

Pick from the high level API:

use avr_boot::PageBuffer;

let address: u16 = 0x1000;
let data = [0xffff; PageBuffer::LENGTH];
let buff = PageBuffer::new(address);
buff.copy_from(&data);
buff.store();

Or the low level one:

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

let page_address: u16 = 0x1000;
for w in 0..SPM_PAGESIZE_WORDS {
    spm::fill_page((page_address + (w * 2) as u16), 0x1234);
}
spm::erase_page(page_address);
spm::write_page(page_address);
spm::rww_enable();

Check out the examples module for more usage examples

Modules

spm

Low level API for calling bootloader functions

Structs

Address

16 or 24 bit program memory address

DataPage

NewType, an array of memory the same size as the page buffer

PageBuffer

Representation of the spm page buffer.

Constants

SPM_PAGESIZE_BYTES

Total size of the SPM page buffer, for the current MCU target

SPM_PAGESIZE_WORDS

Total length in 16 byte words of the SPM page buffer, for the current MCU target