This was a great video. It was particularly cool to see you go through the whole process in KiCAD to build out your custom board. Most people would have skipped the nitty-gritty and just said "and here's the board I made!" A couple of minor tips/suggestions: It was kinda neat to see you going through the process of creating a custom footprint and everything, but you really didn't need to actually do that part. The holes for the headers will have the same footprint as any DIP-24 chip does, so you could have just used one of the existing DIP-24 footprints already in the KiCAD footprint libraries.. Also, when creating the schematic symbol, you don't need to put the pins in order, and it's arguably more convenient if they're grouped by function instead (like they are on the 27C128)... Also, if you wanted to make the board smaller, you could overlay the 27128 footprint on top of one of the pin headers, but just offset a bit... Actually, if you moved the 74LS08 over to the left one, and put the 27128 on top of the right one, almost all of the data/address pins should line up between the two and it would make trace routing pretty trivial (this is actually a common technique with this sort of ROM adapter board because the pinouts are mostly backwards-compatible between the different size DIP ROM chips already).
Thanks for the encouragement! And thanks for letting me know about the footprints and layout. I was pretty much figuring most of the KiCAD things out (including routing strategies) as I went along when I recorded!
Thanks! It continues to be a lot of fun doing the implementation. Bubbling along on one of my back burners is a project for a TTL computer with a zero-argument ISA…
This was a great video. It was particularly cool to see you go through the whole process in KiCAD to build out your custom board. Most people would have skipped the nitty-gritty and just said "and here's the board I made!"
A couple of minor tips/suggestions:
It was kinda neat to see you going through the process of creating a custom footprint and everything, but you really didn't need to actually do that part. The holes for the headers will have the same footprint as any DIP-24 chip does, so you could have just used one of the existing DIP-24 footprints already in the KiCAD footprint libraries..
Also, when creating the schematic symbol, you don't need to put the pins in order, and it's arguably more convenient if they're grouped by function instead (like they are on the 27C128)...
Also, if you wanted to make the board smaller, you could overlay the 27128 footprint on top of one of the pin headers, but just offset a bit... Actually, if you moved the 74LS08 over to the left one, and put the 27128 on top of the right one, almost all of the data/address pins should line up between the two and it would make trace routing pretty trivial (this is actually a common technique with this sort of ROM adapter board because the pinouts are mostly backwards-compatible between the different size DIP ROM chips already).
Thanks for the encouragement! And thanks for letting me know about the footprints and layout. I was pretty much figuring most of the KiCAD things out (including routing strategies) as I went along when I recorded!
Never used FORTH, but this is pretty cool..
Thanks! It continues to be a lot of fun doing the implementation. Bubbling along on one of my back burners is a project for a TTL computer with a zero-argument ISA…