flutterby-rs

Keyboard firmware implemented in Rust.

It doesn't do anything useful yet!

Building for atmega32u4 devices (ergodox-ez, feather32u4)

• First build the cross compiler per these instructions: https://github.com/avr-rust/rust (this will take a couple of hours, but you only need to do it once)
• Then build the examples from this repo:

$ XARGO_RUST_SRC=$HOME/avr-rust rustup run avr-toolchain \
     xargo build --target avr-atmega32u4 --release --verbose --examples

To flash it to the target device:

$ avr-objcopy target/avr-atmega32u4/release/examples/blink.elf -O ihex target/target.hex
$ avrdude -p atmega32u4 -U flash:w:target/target.hex:i -cavr109 -b57600 -D

There's a helper script for building and running a given example:

$ ./run.sh blink

This makes some assumptions about the location of the avr-rust source and which port my device is attached to.

Debugging Using simavr

You need to install simavr and avr-gdb for yourself. On the mac you can do this as a one-time setup:

$ brew install avr-gdb
$ brew install --HEAD simavr

(this may take a while as it may need to build gcc)

Then you can use the sim.sh script to run an example under the simulator. There's no GUI or other visual output for this, but it does start paused and waiting for you to attach with gdb.

In one window:

$ ./sim.sh blink
    Finished release [optimized + debuginfo] target(s) in 0.0 secs
 * You can connect to the sim using
avr-gdb target/avr-atmega32u4/release/examples/blink.elf -ex "target remote :1234" -tui
+ simavr -g -m atmega32u4 -f 8000000 -v -v -v -t target/avr-atmega32u4/release/examples/blink.elf
Loaded 2486 .text at address 0x0
Loaded 110 .data
avr_gdb_init listening on port 1234

Then in another window run the gdb command that it printed above:

$ avr-gdb target/avr-atmega32u4/release/examples/blink.elf -ex "target remote :1234" -tui