Weavie is an ongoing project to create a tiny, physical weaving pattern computer using only 32-bit ARM assembly. I wanted to learn more about embedded development and assembly programming, and building a weaving pattern editor seemed like a fun challenge. Weavie is built for the STM32 board, and has its own basic emulator based on Rust and Unicorn.

All dependencies are defined in shell.nix. Run:

nix-shell

Or install using your preferred package manager.

make

• Connect the BOOT0 (B0) pin to the 3.3V PIN. This enables the DFU bootloader mode.
• Connect the board to the USB port.
• Flash the chip:

make flash

To run in QEMU:

make qemu

Restarting QEMU inside gdb:

monitor system_reset

Exiting QEMU:

Ctrl-A X

Debugging in gdb:

make debug

Step through assembly instruction:

si

Inspect register state:

info registers

Inspect memory address:

p/x 0x40020800
x $r2
x/t $r1
x/10x $r1
x/20c $r1

• Board: Adafruit Feather STM32F405 Cortex M4
• Display: Adafruit SHARP 2.7"
• J-Link: SEGGER J-Link EDU Mini
• Keys: NeoKey - Four Mechanical Key Switches

• 3.3V to display VIN (power)
• GND to display GND (ground)
• SCK to display CLK (clock)
• MO (MOSI) to display DI (data input)
• PIN6 to display CS (chip-select)

• How to Read a Weaving Draft
• Reading a Weaving Draft

• STM32F405 Datasheet
• STM32F405 Reference Manual
• Adafruit STM32F405 Feather Express Pinouts
• Adafruit NeoKey 1x4 Pinouts
• SHARP Display Datasheet
• Sharp Memory Display Wiring Guide

• Hello, world" in ARM assembly
• Bare-metal C programming on ARM
• "Bare Metal" STM32 Programming (Part 1): Hello, ARM!
• A bare metal programming guide (ARM microcontrollers)
• HelloSilicon: An introduction to ARM64 assembly on Apple Silicon Macs
• ARM Assembly Internals & Reverse Engineering
• Emulating an STM32F4 in QEMU to test ARM assembly
• Programming of ARM Cortex-M microcontrollers
• SPI: The serial peripheral interface
• Hubris STM32F4 config