Colin Maykish's Mackerel 68ks Bring Motorola's Popular Processors to a Single-Board Computer Range
The Motorola 68008-based Mackerel-08 is the first in the family to swim, to be followed by increasingly powerful members of the shoal.
Maker and vintage computing enthusiast Colin Maykish is building a fishy series of single-board computers dubbed the Mackerel 68ks — all powered by variants of Motorola's classic 68000-series microprocessors.
"The Mackerel 68k is my series of home-built computers based on the Motorola 68000 family," Maykish explains. "I am building it from the ground up in phases starting with the baby of the family, the 68008. As my understanding and experience with the system improves, I plan to add additional functionality and support for higher-end CPUs in the 68k line-up."
The Motorola 68000 launched in 1979 as a 16/32-bit successor to the company's original 6800, designed to head off competition from rival Intel's 8086 — with the design brief to deliver something twice as powerful, or the same performance at half the cost. The parts would find a home in a range of devices, from personal computers like the Apple Macintosh and Commodore Amiga to games consoles like the Sega Genesis and even arcade machines.
Maykish's creations bring the 68k back to its roots, delivering a personal computer in single-board computer form — and starting with the Mackerel-08. "This is the first (and as of now, only) iteration of Mackerel," Maykish explains. "Using the 52-pin PLCC version of the Motorola 68008, it has a 4MB address space and runs uClinux 2.0. The hardware includes the CPU, 512kB of ROM, up to 3.5MB of RAM (2MB typically installed), and a XR68C681 DUART chip for timer and serial port. It currently runs at 10MHz."
That's not where the fishy vision ends, though: Maykish is currently making the transition from a multi-board prototype on a custom 80-pin backplane to the single-board variant, PCBs for which have recently been delivered and tested, after which he plans to make a more powerful Mackerel-10 based on the Motorola 68010 and featuring persistent storage. This is to be followed by the Mackerel-30, powered by the 68030 and able to run a full Linux kernel thanks to the inclusion of a memory management unit (MMU), and the top-end "Big Mack" with a 68040 running at 40MHz and with 256MB or more of memory.
More information is available on Maykish's Hackaday.io page, while hardware design files and firmware source code are available on GitHub under an unspecified open-source license.