The motherboard

A project log for Motorola 68000 computer

A mc68k-based computer motherboard, some expansion cards, and a very basic multitasking OS, all built from scratch.

StuartStuart 08/18/2015 at 10:040 Comments

Here's another picture of the board - this time with RAM modules, ATA CompactFlash card, RS232 cable and power supply plugged in.

The board requires a regulated 12V input. It generates a 5V logic supply using an LM2678 (the package mounted to the large heatsink at the rear of the board). A four-pin Molex socket provides 12V and 5V for an external hard drive. At the moment my mass storage is a CompactFlash card on a CF-to-ATA adaptor board.

The serial cable connects to a USB-RS232 converter, which is plugged in to my development PC. The PC runs an Ubuntu virtual machine that hosts an m68k-elf-gcc cross-compiler and toolchain. I use PuTTY for interactive sessions with the board.