rust_on_msp

Simple blinking LED example that runs on MSP430.

This is a fork of the original rust_on_msp made for the MSP430FR4133

Compiling

This project can be compiled using nightly rust and xargo.

Tested using version rustc 1.16.0-nightly (4ecc85beb 2016-12-28)

Steps:

• First, install msp430-elf-gcc compiler, and make sure it is in your $PATH. You can get it from here.
• Install nightly rust: $ rustup default nightly
• Until issue #38824 is fixed, we need to use older version of nightly compiler. You can get it using this commands:

rustup default nightly-2016-12-29
rustup override set nightly-2016-12-29
rustup component add rust-src

• Install xargo: $ cargo install xargo

• Build the project: $ make

• or you can build it using xargo directly (if you don't like make)

  $ xargo build --release --target msp430

• Flash the firmware using mspdebug: $ make prog

How it works

• This project is does not use default startup code from gcc, so a reset handler should be defined like this:

#[no_mangle]
#[link_section = "__interrupt_vector_reset"]
pub static RESET_VECTOR: unsafe extern "C" fn() -> ! = main;

RESET_VECTOR is just a function pointer that gets placed inside a special section called __interrupt_vector_reset and is pointing to main function, so it will be called on reset. Other interrupts may be defined the same way for example __interrupt_vector_timer0_a0, but it is not possible to use interrupts yet (other than reset), because rust doesn't have a special calling convention for MSP430 interrupts. A workaround would be to use #[naked] functions. You can follow the discussion here: #38465

Porting to other boards and MCUs

To run this code on the other boards and MCUs, you need to change it in few places:

• Get a linker script for your MCU from msp430-elf-gcc include directory, and place it inside ldscripts folder. (Don't forget to get *_symbols.ld one as well).

The MSP430 package contents contains ldscripts, e.g on Ubuntu & Debian distro's this can be found under /usr/msp430/lib/ldscripts post install of the msp430mcu package.

• Modify .cargo/config file so it would point to your ld script from step 1 and change linker flags to match your MCU name.
• Modify build.rs script so it would copy the right ld script from step 1.

Board

I am using TI LaunchPad board with MSP430FR4133 MCU, but it is easy to port this code for any other board or MCU.