My4TH Light Computer Board
My4TH Light Computer Board
What is it?
The My4TH Light is the big brother of the My4TH XS computer board — a compact, TTL-based Forth 2012 computer with significant upgrades over its smaller sibling. Most notably, it features an I2C bus running at 83 kHz, eight times faster than the original My4TH board, making it an ideal interface for connecting LCD displays, I/O expanders, and sensor breakout boards.
The larger ROM also allows a much richer firmware: 295 standard Forth words, built-in floating point support, and software drivers for I2C-based LCDs and GPIO expanders are all included out of the box — no expansion modules required.
Why did you make it?
The My4TH Light was designed to extend the My4TH platform for users who need faster I2C communication and a richer built-in Forth environment. By moving floating point and I2C drivers into ROM, the system is immediately productive without requiring EEPROM expansion modules for common tasks. It’s a capable, self-contained Forth computer in a compact 90×83mm footprint, ideal for learning, experimentation, and embedded projects.
What makes it special?
- Fast I2C bus at 83 kHz — 8× faster than the original My4TH; ideal for LCD, sensor, and I/O expander connectivity
- Forth 2012 OS — 295 standard words included in ROM
- Built-in floating point support — no expansion module needed
- I2C driver support — built-in drivers for I2C LCDs and general-purpose I/O port expanders
- Proven ALU-less design — 13 logic ICs, 3 memory chips
- Memory: 32KB EPROM + 8KB SRAM + optional 64KB EEPROM
- Clock speed: fixed 8 MHz
- TTL-level UART at 4800 baud
- Compact PCB: 90×83mm
- Optional PS/2 keyboard for direct input
- Optional Versaterm terminal interface
Options Available
- PS/2 Keyboard: Yes / No
- Versaterm: Yes / No