Simple blink program written in Rust for the Adafruit Feather M0 board.
This project has been generated using the cortex-mo-quickstart.
What follows is explicit for the Adafruit Feather M0 and this project.
To build embedded programs using this template you'll need:
-
Rust 1.31, 1.30-beta, nightly-2018-09-13 or a newer toolchain. e.g.
rustup default beta -
The
cargo generatesubcommand. Installation instructions. -
rust-stdcomponents (pre-compiledcorecrate) for the ARM Cortex-M targets. Run:
$ rustup target add thumbv6m-none-eabi thumbv7m-none-eabi thumbv7em-none-eabi thumbv7em-none-eabihfNOTE: This is the very short version that only covers building programs. For the long version, which additionally covers flashing, running and debugging programs, check the embedded Rust book.
- Before we begin you need to identify some characteristics of the target device as these will be used to configure the project:
-
The ARM core. e.g. Cortex-M3.
-
Does the ARM core include an FPU? Cortex-M4F and Cortex-M7F cores do.
-
How much Flash memory and RAM does the target device has? e.g. 256 KiB of Flash and 32 KiB of RAM.
-
Where are Flash memory and RAM mapped in the address space? e.g. RAM is commonly located at address
0x2000_0000.
You can find this information in the data sheet or the reference manual of your device.
In this project we are using the Adafruit Feather M0 (and older version).
- Instantiate the template.
$ cargo generate --git https://github.com/rust-embedded/cortex-m-quickstart
Project Name: blink-cortex-m0
$ cd app- Set a default compilation target. There are four options as mentioned at the
bottom of
.cargo/config. For the Adafruit Feather M0, which has a Cortex-M0 core, we'll pick thethumbv6m-none-eabitarget.
$ Edit .cargo/config[build]
# Pick ONE of these compilation targets
target = "thumbv6m-none-eabi" # CortexM0 and Cortex-M0+
# target = "thumbv7m-none-eabi" # Cortex-M3
# target = "thumbv7em-none-eabi" # Cortex-M4 and Cortex-M7 (no FPU)
# target = "thumbv7em-none-eabihf" # Cortex-M4F and Cortex-M7F (with FPU)- Edit the dependencies in
.\Cargo.toml
[dependencies]
cortex-m = "0.6.0"
cortex-m-rt = "0.6.10"
cortex-m-semihosting = "0.3.3"
panic-halt = "0.2.0"
feather_m0 = "0.10.1"Orginally tried:
[dependencies] panic-halt = "0.2.0" feather_m0 = { git = "https://github.com/atsamd-rs/atsamd" }This worked, but it seems some changes in the quickstart repo have caused a build error. Maybe this will work later.
- Enter the memory region information into the
memory.xfile. This information comes from another project.
MEMORY
{
/* Leave 8k for the default bootloader on the Feather M0 */
FLASH (rx) : ORIGIN = 0x00000000 + 8K, LENGTH = 256K - 8K
RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 32K
}
_stack_start = ORIGIN(RAM) + LENGTH(RAM);-
Place the code in
main.rsunder./src -
Build the appplication.
$ cargo build- Copy the generated code over to a binary suitable for flashing.
$ objcopy -O binary .\target\thumbv6m-none-eabi\debug\blink-cortex-m0 .\target\thumbv6m-none-eabi\debug\blink-cortex-m0.binAlso experimented with:
$ cargo objcopy -- -O binary .\target\thumbv6m-none-eabi\debug\blink-context-m0.binNeed to first install cargo-binutils.
But had little success!
- Flash the microcontroller. Note that the old version of the Feather M0 being used does not have the HF2 bootloader so have to use this the
bossaccommand. Windows:
$ bossac -p COM7 -e -w -v -R .\target\thumbv6m-none-eabi\debug\blink-cortex-m0.binUnix:
For version 1.9! Note the offset! Getting this wrong can brick the microcontroller.
$ bossac -p COM7 -e -w -v -R --offset=0x2000 .\target\thumbv6m-none-eabi\debug\blink-cortex-m0.bin - The red led and any led connected to pin D7 should blink.
Do not think that I can use OCD for debugging as the feather board does not have the corrresponding debugger chip. Problem as most of the examples in the cortex-m-quickstart use this to output something.
Note that openOSD is supplied with the Ardunino IDE. See this video.