pybadge-high

Goal of this crate is to provide high level hardware abstraction layer for the pybade and the edgebadge. It should allow people with no/less knowledge of rust and embedded hardware, to program the boards mention before. If you try to do anything hardware-near or usinig additonal expensions, you should probably use the more hardware-near the edgebadge or atsamd_hal crate instead.

Setup

Installation

• Install rustup. I recommand to use the package manger of your operation system. Alternative you can install it from https://www.rust-lang.org/tools/install

• install the rust thumbv7em-none-eabihf target. (the architecture of the micronctroller)

rustup target install thumbv7em-none-eabihf

• optional: install nightly toolchain for better doc (only relevant if you build the doc by yourself).

rustup toolchain install nightly --target thumbv7em-none-eabihf

• install the hf2-cli flasher

Create your Project

• Create a new rust project.

cargo new my-app

• Add a .cargo/config.toml with the following content, to define target architecture and flasher

[target.thumbv7em-none-eabihf]
runner = "hf2 elf"
#runner = 'probe-run --chip ATSAMD51J19A'

[build]
target = "thumbv7em-none-eabihf"
rustflags = [

  # This is needed if your flash or ram addresses are not aligned to 0x10000 in memory.x
  # See https://github.com/rust-embedded/cortex-m-quickstart/pull/95
  "-C", "link-arg=--nmagic",

  "-C", "link-arg=-Tlink.x",
]

• Add this crate as dependency

cargo add pybadge-high

• optional: add this to your cargo.toml for better optimizations

[profile.release]
codegen-units = 1 # better optimizations
debug = true # symbols are nice and they don't increase the size on Flash
lto = true # better optimizations

• Addjust your main.rs

You need to do some changes at your main.rs. First you must disable the rust standart libary by adding #![no_std], because it is not supported by the pybadge. This does also mean you can not use the default main function any more and must disable it with #![no_main]. But because we still need a main function to enter the code we need to define our own main with #[entry]. This main function does never return (!). Otherwise the pybadge would do random stuff after the program has finish. So we need a endless loop. To get access to the peripherals of the pybadge, like display, buttons, leds etc you call PyBadge::take(). This function can only called once at runtime otherwise it will return an Error.

#![no_std]
#![no_main]

use pybadge_high::{prelude::*, PyBadge};

#[entry]
fn main() -> ! {
	let mut pybadge = PyBadge::take().unwrap();
	loop {}
}

When a program does panic, the red led at the back of the board starts flashing. If the bluescreen(default) feature is enable, the display does show the postion of the error. When the beep_panic feature is enable, the pybadge also beep for 3 seconds.

Flashing:

To flash you program, put your device in bootloader mode by hitting the reset button twice. After this excute

cargo run --release

The display does not work until you have press the reset button of the pybadge after flashing.

Feature-flags

This crate has spilt functionallity in multiple feature flags. See the rust book for more information about features. Enabling only the feauters, which are needed, helps to keep the binary size small and reduce the number of needed dependencies.

The following features are aviable:

• beep_panic — beep for 3 seconds, when rust pancics

• bluescreen (enabled by default) — show a bluescreen with error postion, when rust pancics

• bluescreen-message-nightly — show also error message at bluescreen, when rust panics.

  This features depends on rust nightly features and needs the nightly toolchain. It has no effect, when compiled with stable. Because it use nightly features it might break in future rust versions.

• neopixel — support for the Neopixel below the screen

• usb — support for serial communication over usb

• pwm_sound — support for single frequenc sound

• time (enabled by default) — support for time measurement