Controlling electronics with the Commodore 64 user port - Part 1
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- Опубликовано: 3 авг 2024
- This is the first part of a series where I explore the possibility to use the user port on an old Commodore 64 8-bit computer from the 80-s, to communicate with other electronic devices, self made or for example an Arduino device.
In this part I construct the cable and connector I need, then I power a simple LED circuit from the Commodore.
Electronicts kits I have purchased:
- Arduino Starter Kit: www.kjell.com/no/produkter/el...
- Jumper wire kit: www.ebay.com/itm/283551710430
- UNO R3 basic kit: www.ebay.com/itm/143443111179
- Electronics Component Basic Starter Kit: www.ebay.com/itm/283679804520 
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A very interesting project. That user port cover turned out excellent. I am excited to see what you come up with once the Arduino gets connected.
Thanks. I have part 3 ready soon with the arduino :-)
Thanks for the project video. Back in the early 80's we used a VIC 20 with a SP0256-AL2 phoneem processor circuit out of the BLUE BOOK. That would be another interesting project
Wow! What timing - I am furously getting busy rejoining the Commodore community. I want to turn a C64 into an oscilloscope so I can further use it as an "octopus."
Sounds great!
This is so funny! I created this back in 1990 for my highschool graduation project for computer class. I initially started using BC547 as LED drivers. Then I found a 74541 and that made it a lot quicker :)
I used and external power supply to off load the CIA because 100mA isn’t a lot and I was afraid that if I fucked up ghe school’s 64 I would not get a passing grade :) Although my calculations showed that I could run all 8 LEDs and draw ~80mA I was a bit chicken shit :)
I got a very good grade and it taught me more than the first semester of engineering college.
I actually demonstrated a binary counter in basic vs machine language. And used another C64 with userport as input as a frequency counter and showing that binary counting is an exact means of frequency dividing.
The teacher and the 3 exam committee members were impressed. Me and my buddy actually made tools for CCITT 5 hacking (phreaking) and we used the C64 as a means to accurately, send the sys-forward tones. Which initially I generated with the SID but later we did with logic as it was more accurate. So the whole 8 LED and one input counter was a day’s work :) The easiest A+ (10) ever :)
Thanks!
I like the 3D printed cable housing :) Tip, put the pin header in a breadboard and solder it there :) I have a few bad breadboards I got from ordering from ebay that I mainly use to solder pin headers. Looking forward to part 2. I'm thinking there must be a open source project out there of output buffers for the user port ?
Good tip. I will do that next time. Have a lot of breadboards
This type of edge connector has moulds in between the contacts allowing little plastics as coding to match the gaps on the C64's mainboard. At least this is what had been done back in the days. Or maybe because our then company wanted to make it fully fail safe. 🤓
Is the connector key too small to print? You might be able to make a label for the connector with the extra-small font on your label maker.
So-called "insulform" (double layer) heat shrink can be used to give support at the connector end and make a nice finishing touch. Double layer tubing has an inner "adhesive" layer that flows to fill voids and is very sturdy. The header pins are a nice touch.
I remember an I/O project from the Explorer's Guide to the Sinclair ZX-81 and TS-1000 that used an 8255 Programmable Peripheral Interface to do real-world I/O. This seems a whole lot simpler and more elegant. Neat stuff!
Hello
I would like to control 2 outputs via 2 5Volts input signals.
Can you help me?
Hello
I would like to command a greater number of doors.
But I want to do it in order
port 1 = 10 seconds on and then off
port 2 = 15 seconds on and then off
port 5 = 30 seconds on and then off
can you help me?