snd/rust-feather-m4

experiments with rust on the Adafruit Feather M4 Express microcontroller

rust feather M4

experiments with rust on the Adafruit Feather M4 Express (Adafruit Industries 3857) board with the ATSAMD51J19 microprocessor featuring the ARM Cortex-M4F microprocessor core

run

./build.sh {name of one in src/bin}

./flash.sh {name of one in src/bin}

./build-and-flash.sh {name of one in src/bin}

install

install rust:

curl https://sh.rustup.rs -sSf | sh
rustup update

install component for ARM M4 targets:

rustup target add thumbv7em-none-eabihf

install bossac (https://github.com/shumatech/BOSSA) which we'll use to upload our binary to the feather M4s flash memory:

git clone https://github.com/shumatech/BOSSA.git
cd BOSSA
make
cp bin/bossac ~/bin

install arm-none-eabi-objcopy which makes *.bin files out of *.elf files (https://stackoverflow.com/questions/2427011/what-is-the-difference-between-elf-files-and-bin-files):

brew tap PX4/homebrew-px4
brew update
brew install gcc-arm-none-eabi

enter this repository:

git clone git@github.com:snd/rust-feather-m4.git
cd rust-feather-m4

board

https://www.alliedelec.com/product/adafruit-industries/3857/71458403

https://www.digikey.com/product-detail/en/adafruit-industries-llc/3857/1528-2648-ND/9553567

ATSAMD51J19 microprocessor

by microchip (source: https://twitter.com/microchipmakes/status/1017405803349839872)

microprocessor: https://www.microchip.com/wwwproducts/en/ATSAMD51J19A https://learn.adafruit.com/adafruit-feather-m4-express-atsamd51/downloads https://www.digikey.com/product-detail/en/adafruit-industries-llc/3857/1528-2648-ND/9553567

• 120MHZ
  • source: https://www.adafruit.com/product/3857
• flash length = 512KB
  • source: https://www.adafruit.com/product/3857
• RAM length = 192KB
  • source: https://www.adafruit.com/product/3857
• flash origin address = 0x00000000
  • source: https://www.mouser.com/datasheet/2/268/60001507A-1130176.pdf
    • After Reset has been released, the CPU starts fetching PC and SP values from the Reset address,0x00000000. This points to the first executable address in the internal Flash memory
    • search for Physical Memory Map
• RAM origin address = 0x20000000
  • source: https://www.mouser.com/datasheet/2/268/60001507A-1130176.pdf
    • search for Product Memory Mapping Overview
    • search for Physical Memory Map
  • RAM is commonly located at address 0x20000000
    • source: https://github.com/rust-embedded/cortex-m-quickstart

awesome resources

• https://github.com/atsamd-rs/atsamd - for using the GPIO, clock, serial interfaces, etc on the M4
• https://rust-embedded.github.io/book/
• https://github.com/rust-embedded/awesome-embedded-rust
• https://github.com/rust-embedded/alloc-cortex-m - a heap allocator for Cortex-M processors
• https://github.com/johnthagen/min-sized-rust - How to minimize Rust binary size
• https://github.com/RazrFalcon/cargo-bloat - Find out what takes most of the space in your executable
• https://jamesmunns.com/blog/tinyrocket/ - making tiny rust executables

files

• memory.x contains specification of the memory layout of the target chip

steps taken to initialize this project

cargo install cargo-generate

cargo generate --git https://github.com/rust-embedded/cortex-m-quickstart --name rust-feather-m4