gschwaer/msp430-zig-minimal-example

Blink In Zig For MSP430 Microcontrollers

Blink In Zig For MSP430 Microcontrollers

I wanted to experiment a little with Zig lang. And I saw that it has a MSP430 backend. So I set out to try and run some Zig on an MSP430. This is the journey to a minimal blink example to get started.

The experiment:

1. Starting with a known good blink example in C (./blink-c).
   • Well, what can I say, it blinks.
2. Create minimal blink example in assembly (./blink-asm).
   • Understand what is really required by reading a) the manual and b) the generated assembly from blink-c.
   • To get C out of the loop completely.
3. Try to replicate it with Zig (./blink-zig).
   • See Learnings.

Relevant Documents

• MSP430G2xxx User's Guide (really good!)
  • includes msp430 register and assembly reference (nice!)
  • includes what is required to boot (thanks!)
• MSP430G2x53 Datasheet

Hardware Requirements

• To follow along:
  • TI MSP430 LaunchPad Development Tool (MSP-EXP430G2)
  • MSP430G2553 (included in LaunchPad Kit)
• Basically usable for every MSP430, just adapt the build and run procedure.

Software Requirements

• mspdebug (Debian/Ubuntu: sudo apt install mspdebug) - to flash and debug the code on the chip
• msp430-elf-* MSP430-GCC-OPENSOURCE toolchain from TI (link)
  • "Mitto Systems GCC 64-bit Linux - toolchain only" -> extract into repo-dir/msp430-gcc-9.3.1.11_linux64 (or change path in .env)
  • "Header and Support Files" -> extract into repo-dir/msp430-gcc-support-files (or change path in .env)

How-To

First set up your terminal environment:

source .env

(Must be executed in the repo directory, in subfolders use cd .. && source .env && cd -.)

Enter the subdirectory of choice, then:

1. Build: ./build.sh
2. Inspect: ./inspect.sh (the generated assembly)
3. Run: ./run.sh (then enter prog blink.o and run)