Using Zinc Externally with a Teensy 3.1 or 3.2

This project is an example of how you can setup an external project using Zinc to target the Teensy. The actual example used here is one taken from the Zinc examples, but with this infrastructure in place, you can create whatever you want.

Pre-requisites

OS X

• Install rustup
  • $ rustup update nightly-2016-05-12
  • In your project dir: $ rustup override set nightly-2016-05-12
• Install arm-none-eabi gcc suite (for cortex-m4)
  • $ brew cask install gcc-arm-embedded
• Setup the thumbv7em-none-eabi target
  • $ echo -e '[target.thumbv7em-none-eabi]\nlinker = "arm-none-eabi-gcc"\nar = "arm-none-eabi-ar"\n' >> ~/.cargo/config
• Install the Teensy Loader CLI
  • $ brew install -dv --HEAD teensy_loader_cli

Building the Example

The code can be built with cargo.

$ cargo build --release --target=thumbv7em-none-eabi

This will generate an object file, to turn this into a bin file or hex file you will need to run objdump on the resultant binary. E.g.

$ objdump -O ihex ./target/thumbv7em-none-eabi/release/blink blink.hex

Since you are like to need to type this quite frequently, you may want to create a Makefile like this one to reduce the number of commands you need to type.

Flashing the Teensy

$ teensy_loader_cli -s --mcu=mk20dx256 -v ./target/thumbv7em-none-eabi/release/blink.hex
Teensy Loader, Command Line, Version 2.0
Read "target/thumbv7em-none-eabi/release/blink.hex": 3236 bytes, 1.2% usage
Soft reboot is not implemented for OSX
Waiting for Teensy device...
 (hint: press the reset button)
Found HalfKay Bootloader
Read "target/thumbv7em-none-eabi/release/blink.hex": 3236 bytes, 1.2% usage
Programming....
Booting

Creating Your Own Poject Using Zinc

Step 1: Create a new rust project

$ rust new --bin --vcs git rust-teensy3-blink
$ cd rust-teensy-blink

Step 2: Set up your Cargo.toml

Add the following to Cargo.toml, replacing the information preset here with information that makes sense for your MCU, binary, etc.

[package]
name = "rust-teensy3-blink"
version = "0.1.0"
authors = [YOU, "Geoff Cant <nem@erlang.geek.nz>", "Paul Osborne <osbpau@gmail.com>"]

[dependencies.zinc]
git = "https://github.com/Gyscos/zinc.git"
branch = "crazy"
features = ["mcu_k20"]

[dependencies.macro_platformtree]
git = "https://github.com/Gyscos/zinc.git"
branch = "crazy"
path = "macro_platformtree"

[dependencies.ioreg]
git = "https://github.com/Gyscos/zinc.git"
branch = "crazy"
path = "ioreg"

[dependencies.platformtree]
git = "https://github.com/Gyscos/zinc.git"
branch = "crazy"
path = "platformtree"

[dependencies.rust-libcore]
version = "*"

[[bin]]
name = "blink"
path = "blink.rs"

Step 3: Grab a target specification

Grab a suitable target specification from those available in the root of the Zinc repository (thumbv7em-none-eabi.json for the Teensy 3.1 and 3.2).

Step 4: Tell rust about your toolchain

This usually requires putting a couple lines like this in your .cargo/config so that Rust knows to use a proper cross-linker for your target:

[target.thumbv7em-none-eabi]
linker = "arm-none-eabi-gcc"
ar = "arm-none-eabi-ar"

[target.thumbv7m-none-eabi]
linker = "arm-none-eabi-gcc"
ar = "arm-none-eabi-ar"

Step 4: Automate artifact generation

You can start with the Makefile from the example and go from there.

Step 5: Create!

Write your code using Zinc!