Multicomp revisited.

Way back in April 2015 I wrote about building an FPGA computer based on Grant Searles Multicomp.

To be honest, it’s not had a lot of use. It has sat, largely unloved, in a cupboard awaiting redisovery. Well. in a roundabout way I have rediscovered it.

Back in September last year, I exhibited a few retro machines at the Centre for Computing History‘s Retro Festival with an old friend. There were quite a few exhibitors from all over the place and one, Neal, was demonstrating the multicomp as a fully loaded 6809 machine. The really nice feature for me was that Neal had used a PCB to build his whereas mine was using a bit of blob board I had kicking around. What was nicer was that Neal had a spare blank board that he was willing to pass on to me.

This board has been sitting on the “Shelf of good intentions” until the right time and its time has come.

Getting started.

The design files for the PCB and instructions can be found on the Retrobrew website and package the information nicely. Be careful when coosing the CF card socket and the RCA connector as there are more than one design of each out there and it’s easy to get a wrong example of each… I have found.

The first step is to solder the connectors and the components for the VGA interface and PS/2 keyboard. This can be considered a minimal system and is a good place to stop and see how you are doing.

At this stage you should have a working 6809 machine with VGA output and 2k of built-in RAM.

This is where I’m up to now. More to follow shortly.

 

 

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