Wire Wrap Parts for Homebrew Computer

Thread Starter

Leland Clayton

Joined Nov 4, 2016
7
I am working on a Homebrew Z80 computer. Instead of using a bunch of 40pin DIPs I want to use the z80c90 KIO that is a PLCC 84 pin IC. However since I am doing this as a Wire Wrap build I am trying to find a Two or Three Level socket. I already tried to use a standard thru-hole socket and attach some machined wirewrap pins but the two PLCC sockets I tried have super flimsy pins that doesn't grip too well.
 

Janis59

Joined Aug 21, 2017
906
Waaaaaw! First I made it (Intel-8080 computer) about 1975 or 76 - soon after invention. Do You think it have still any thoughtful application for 2 MHz and 8 bits, in the epoch when every Raspberry is near the same strong like 5 year old table computer and even the poor-man aide the Arduino is 4-fold faster over 8080. I see Your Project like some artist would say - I shall sing like a Beatles or sing like a Rolling Stones, isnt so? In those times we made here a wire thermal gluing machine (two hot rolls) to produce the beautiful flat cables for 8080. Because the only alternative except the primitive bunch was knitting the flat cable, actually look nice, works well, only the time for this effort is badly long. In hour may knit about few meters of 32 wire cable. How to knit a widebands, that are teached to every girl at 1st class, just ask em. If I remember right, jut take the all wires flat and fix somewhere, then give a numbers, 1...32. Then pull the 1st and cross with all the rest of wires, 2nd from above, 3rd from down, 4th from above, 5th from down etc until the 32. Then take a number 2 and do the same as with number 1. After 32 steps make tyhe same about wire number 3 and then go, go, go, until the full 32 crossing cycle is made. Then begin again with the 1st.
 
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WBahn

Joined Mar 31, 2012
24,981
Waaaaaw! First I made it (Intel-8080 computer) about 1975 or 76 - soon after invention. Do You think it have still any thoughtful application for 2 MHz and 8 bits, in the epoch when every Raspberry is near the same strong like 5 year old table computer and even the poor-man aide the Arduino is 4-fold faster over 8080.
My guess is that he is not doing this because of some "thoughtful application", but rather as a means to an educational or just personal satisfaction end.
 

cmartinez

Joined Jan 17, 2007
6,647
I am working on a Homebrew Z80 computer. Instead of using a bunch of 40pin DIPs I want to use the z80c90 KIO that is a PLCC 84 pin IC. However since I am doing this as a Wire Wrap build I am trying to find a Two or Three Level socket. I already tried to use a standard thru-hole socket and attach some machined wirewrap pins but the two PLCC sockets I tried have super flimsy pins that doesn't grip too well.
Have you thought about etching your own PCB's instead of using wire wrap for this project? Etching is hard enough, but wire wrap can be a real nightmare in terms of tracing each connection and the ever present possibility of false contacts. Take a look at this post, and then at this one.
 

JohnInTX

Joined Jun 26, 2012
3,919
Try SchmartBoard:
https://schmartboard.com/schmartboard-ez-plcc-20-84-pins-0-05-pitch-2-x-2-grid-202-0012-01/
This one looks like it would take a SMT PLCC-84 socket and pin it out to .025" sq. wire wrap headers with .100" pitch. If you send them the parts (Fremont, CA) they'll even solder it up for 6.00. Nice.

Other outfits like Aries, ChipQuik make this kind of thing but I didn't see an 84 pin setup.
https://www.digikey.com/products/en/prototyping-fabrication-products/adapter-breakout-boards/643?k=PLCC to DIP

You might try laying out a PCB for the PLCC-wire wrap headers. That would also allow you to locate sensitive things like decoupling caps, oscillators etc. close to the chip. If you use the SchmartBoard, consider tacking the decoupling caps to the back of the board and doing short point-to-point runs to power and ground.
EDIT: there are pads for 0603 SMTs in the corners pinned out to holes that would take a wire wrap pin. That would do it..

It's a cool project and totally doable in wirewrap. Back in the day, I wire-wrapped dozens of microcomputer systems using 8085/Z80/8748/8751/6800/6303 CPUs with good success. Many production computers and control systems were also done in wirewrap. An automated wirewrap station would have an X-Y traverse to locate the wirewrap tip at the pin and tubes of pre-stripped wire on the edges. For each wire, the appropriate tube lit up to indicate the proper wire to use and the XY moved to the pin. The operator wrapped that pin then hit a footswitch and the XY moved to the termination point where the operator made the point-to-point connection. Just too cool.

Properly done with square pins and a good tool and wire, a wire wrap connection is as good or better than solder. If this is your first outing with it let us know and we can offer some lifesaving tips.

Cool project! Good luck.
 
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Thread Starter

Leland Clayton

Joined Nov 4, 2016
7
Building a Z80 from scratch is on my bucket list. I already built a 6800 and a 8088 a few years ago. After the Z80 I'll try my hand with a 6502.

I build these system just for shear fun. Anyone can play with a Raspberry Pi or an Arduino and call themselves an electronics engineer these days. But building something from a handful of ICs is much more enjoyable then slapping a Desktop Computer together let alone a learning experience.

Wire Wrapping is easy as long as you use ChipIDs so you don't get confused what Pin number is what and to use different color wire for different things. I've Wire Wrapped a few boards in my day and yea it can become a nightmare if you let it become a nightmare. I could do the easy route and Etch a PCB or send off some gerber files and have a board or two spun but if I wanted to add more to the system then I would have to make a new board of attempt to make it modular with a back plane and edge cards.

After emailing a few companies I found one that sales the PLCC socket I am looking for. The other two companies wanted me to buy in bulk of 100 units at 50 bucks a pop.

https://www.alliedelec.com/product/winslow-adaptics/wplcc084-t3rc/R1002168/
 

nsaspook

Joined Aug 27, 2009
6,610
Building a Z80 from scratch is on my bucket list. I already built a 6800 and a 8088 a few years ago. After the Z80 I'll try my hand with a 6502.

I build these system just for shear fun. Anyone can play with a Raspberry Pi or an Arduino and call themselves an electronics engineer these days. But building something from a handful of ICs is much more enjoyable then slapping a Desktop Computer together let alone a learning experience.

Wire Wrapping is easy as long as you use ChipIDs so you don't get confused what Pin number is what and to use different color wire for different things. I've Wire Wrapped a few boards in my day and yea it can become a nightmare if you let it become a nightmare. I could do the easy route and Etch a PCB or send off some gerber files and have a board or two spun but if I wanted to add more to the system then I would have to make a new board of attempt to make it modular with a back plane and edge cards.

After emailing a few companies I found one that sales the PLCC socket I am looking for. The other two companies wanted me to buy in bulk of 100 units at 50 bucks a pop.

https://www.alliedelec.com/product/winslow-adaptics/wplcc084-t3rc/R1002168/
Nice. Here's my old Z80 with a little modern on it.
https://forum.allaboutcircuits.com/threads/memio-emulator-for-z80.117003/
 
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