2 ms·

This is very helpful, thank you. In particular thanks for the tip about not lining things up in rows, because that's just what I would have done. I could probab

by cturner 11y ago

This is very helpful, thank you. In particular thanks for the tip about not lining things up in rows, because that's just what I would have done. I could probably write a script so that I could design things in neat rows on a screen, and then it could fit it for me in a tight bunch, and then I could wrap it. Are there smart ways to use decoupling capacitors to get more? How do you get a feel for how much room you have to play with as far as MHz? Is it just a case that you start with something small, and then go up until it breaks? Are there practicalities of what chip generations is possible with wire-wrap? 6502 would be possible with wire-wrap. What about Motorolla 68k? (Also - what is the most sophisticated 68k chip that's still commercially available? Speed and memory addressing are important, MMU is not.)

cmrdporcupine 11y ago
I've seen lots of 68k wire wrapped projects out there on the web. Even breadboarded. I haven't really done any wire wrap projects, just played with it a bit, but I really liked this page for general advice, he seems to know the art well: http://wilsonminesco.com/6502primer/WireWrap.html http://wilsonminesco.com/6502primer/WireWrap.html
pjc50 11y ago
You can get built in decoupling capacitors: https://www.mill-max.com/products/socket/122-XX-XXX-41-801000 https://www.mill-max.com/products/socket/122-XX-XXX-41-80100... You could certainly estimate the clock frequency in advance. The things that are going to cause trouble are transmission line effects (ie pulse length no longer >> wire length), and the usual digital logic critical path constraints: wire and gate delays; clock skew and drive strength; fanout constraints. More decoupling doesn't help you once you have enough to prevent crosstalk through the power supply. Star-routing the power and ground may be a good idea. I've done 20MHz. Coincidentally this is the limit of cheap scopes. This page claims 33MHz is achievable, and gives a good explanation of why: http://www.sigcon.com/Pubs/news/2_8.htm http://www.sigcon.com/Pubs/news/2_8.htm Some good tips: https://www.pjrc.com/tech/8051/dev-board-wirewrap.html https://www.pjrc.com/tech/8051/dev-board-wirewrap.html Reccomendation to use the kind of board with built-in ground plane (sounds good if you can find it): http://www.williamson-labs.com/prototype-lt.htm http://www.williamson-labs.com/prototype-lt.htm For IC availability, check your local Digikey. Note that 68k is still being manufactured as "Coldfire" by Freescale (with slight backwards incompatibility).

by cturner 11y ago

cmrdporcupine 11y ago

I've seen lots of 68k wire wrapped projects out there on the web. Even breadboarded. I haven't really done any wire wrap projects, just played with it a bit, but I really liked this page for general advice, he seems to know the art well: http://wilsonminesco.com/6502primer/WireWrap.html http://wilsonminesco.com/6502primer/WireWrap.html

pjc50 11y ago

You can get built in decoupling capacitors: https://www.mill-max.com/products/socket/122-XX-XXX-41-801000 https://www.mill-max.com/products/socket/122-XX-XXX-41-80100... You could certainly estimate the clock frequency in advance. The things that are going to cause trouble are transmission line effects (ie pulse length no longer >> wire length), and the usual digital logic critical path constraints: wire and gate delays; clock skew and drive strength; fanout constraints. More decoupling doesn't help you once you have enough to prevent crosstalk through the power supply. Star-routing the power and ground may be a good idea. I've done 20MHz. Coincidentally this is the limit of cheap scopes. This page claims 33MHz is achievable, and gives a good explanation of why: http://www.sigcon.com/Pubs/news/2_8.htm http://www.sigcon.com/Pubs/news/2_8.htm Some good tips: https://www.pjrc.com/tech/8051/dev-board-wirewrap.html https://www.pjrc.com/tech/8051/dev-board-wirewrap.html Reccomendation to use the kind of board with built-in ground plane (sounds good if you can find it): http://www.williamson-labs.com/prototype-lt.htm http://www.williamson-labs.com/prototype-lt.htm For IC availability, check your local Digikey. Note that 68k is still being manufactured as "Coldfire" by Freescale (with slight backwards incompatibility).