interrupt_tv

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Project #2: A 16-byte diode ROM board (codeberg.org)
 

Do you need 16 bytes of ROM that you can program with a soldering iron? Well, you're in luck!

I'm working on a larger project that I'll hopefully be sharing here soon, and needed something to display hexadecimal digits on a 7-segment LED display. The non-obsolete ICs that I found could only do binary coded decimal, but I need to be able to display A-F as well. An EEPROM truth table can be used for this, but I also wanted to avoid any programmable ICs. I decided to take an old-school approach and create a diode ROM board.

Diode ROM parts

Diode ROM assembled

Diode ROM in use

My first completed KiCad project: A breadboard adapter for Aries low-profile ZIF sockets in c/electronics@discuss.tchncs.de
[–] interrupt_tv@piefed.world 3 points 1 month ago

Thank you. I agree, it is a really impressive piece of software.

I went with JLCPCB. Cost about $5 for the 5 boards with shipping, which took two weeks. I just added some additional instructions to the readme about getting the boards manufactured. The process seemed daunting before I did it, but it turned out to be really easy.

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My first completed KiCad project: A breadboard adapter for Aries low-profile ZIF sockets (codeberg.org)
submitted 1 month ago* (last edited 1 month ago) by interrupt_tv@piefed.world to c/electronics@discuss.tchncs.de
2 comments fedilink
 

I've been working on Ben Eater's breadboard 6502 computer project for a little while. The pins on the EEPROM sometimes get bent when I pry it out of the breadboard to reprogram it. I was afraid that they'd break eventually, so I looked into getting a Zero Insertion Force (ZIF) socket to put on the board, which should be gentler on the EEPROM's pins. Ran into a few problems though:

  • The pins on ZIF sockets are too short to seat properly on a breadboard. They're designed to be soldered into a printed circuit board.
  • I found a few designs for adapter PCBs that allow a ZIF socket to be used on a breadboard. They're all sized for the common green ZIF sockets, which take up a lot of extra space compared to the chip that they hold.
  • Aries Electronics makes low-profile ZIF sockets that are very compact, but I couldn't find any adapters designed for them.

I eventually decided to solve that last one myself, and I figured I'd share the design in case anyone else might find it useful: