3

Homebrew computing with the C88 and C

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connected to a general-purpose input-output (GPIO)

port. Each of these must be entered into the computer

by hand, one at a time, by toggling wonderfully tactile

metal switches to alter the contents of individual

memory locations.

“Then I decided that’s not big enough, I’m going to

do a bigger one, and that’s why I made the 32-bit one,”

Daniel laughs, referring to the C88’s bigger brother the

C3232 and its hefty laser-cut wooden housing. “It was

pretty much just scaling up what I had, but I wanted to

try some different things. I thought, if I’ve got a 32 ×

32 grid I can definitely emulate the Manchester Baby,

but I wanted my own CPU in there, and I thought while

I’m at it I can have an emulation of the C88 in there, so

the 32-bit one can emulate the C88. I thought I might

as well, I’ve got space, chuck ‘em all in!”

Like the C88, the C3232 is programmed by hand

using toggle switches to alter memory locations one

bit at a time. Unlike the C88, the C3232’s impressive

LED matrix display shines in rainbow colours – a great

crowd puller at the events Daniel tours as a member

of the York Hackspace – while it runs a wider range of

programs, up to and including anything written for the

original Manchester Baby.

“An FPGA is the ultimately flexible piece of

hardware,” Daniel explains. “Unfortunately, at the

moment, it is a lot harder to get into FPGAs, but I

certainly think it’s something hobbyists should be able

to do. It means you can do things like this, and do

it properly, and you end up with something, usually,

that works more efficiently than a microcontroller or

other CPU.”

Like the C88, the C3232 is programmed by

hand using toggle switches to alter memory

locations one bit at a time

”

”

Having designed a processor for the C88 complete

with its own very simple instruction set – an ambitious

project for someone who had never worked with

FPGAs before – Daniel was faced with using that

processor to achieve something. With 64 bits of

memory total that’s a challenge, but one to which

Daniel proved the equal: programs available for the

C88 include a simple calculator, animations which

display on the LED matrix, a dice rolling system, and

even programs for interacting with external hardware

Above

Programs are toggled

into memory by hand,

using tactile switches

Right

The colourful display

of the C3232 is a

large LED matrix