Last modified: Aug 10, 2020, Page views: 1323
Port Breakout with breadboard
Port Breakout, top view
Port Breakout, bottom view
A lot of people today who love Commodore 8-Bit computers enjoy them for their hackability. This
board is one of a host of similar hobbyist products that make prototyping, hacking and exploring
the electronics side of the computer much easier.
A breakout board is one that allows the computer to continue functioning normally, while exposing
the lines of some port or IC socket to the electronics hobbyist, with minimal fuss. This
particular breakout board plugs into the Vic-20's wide expansion port, and has labeled
downward–facing pins that line up with the pin spacing on a standard prototyping breadboard.
The +5 VDC and Ground lines from the expansion port lead to pins which are inserted into the
power rails on the outside edge of the breadboard, and the rest extend a bit further to plug
into the main inner section of the breadboard. A handy reset button is built in, connecting the
expansion port's reset line to ground.
You should not attempt to use one of these breakout boards, unless you are well versed in
electronics and know what you're doing. Any damage you cause to your computer will be your own
It's an incredibly handy board for doing quick prototype or tinker jobs.
jbevren, January 2018
David Wood, also known as Jbevren on IRC, picked up one of these at a computer show. He has been
using it to prototype an EEPROM Shadow Rom. The KERNAL rom from inside the computer has been
pulled, and inserted into the first breadboard. The breakout board connects the breadboard to the
Vic-20's expansion port. The only additional line from the computer required for his project is
the black wire that can be seen sneaking out the corner of the expansion port. That line is
inserted into the Chip Select pin hole of the KERNAL rom's socket on the mainboard.
Looks like Retro Fun!
In this next photo, the final version of the project can be seen. It is the tiny yellow board
into which the KERNAL rom is plugged, near the front right of the mainboard, with 5 colorful
lines coming off it.
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NOTE: Pictured breadboard is not included.