gilhad wrote:
Hello, I just joined in
Here are some my thoughts: (...)
It's never too late and thanks so much for sharing your thoughts, Gilhad
I've made some final adjustments after all the comments (including yours) and ordered a PCB for the entire $25(from JLPCB) including taxes and postage. Will let you know how (or if) my board works once I have it.
I have finally decied to stay with my line drivers. '245 looks like elegant alternative, but as I have 11 LEDs to control.... 2x6 outputs seems more reasonable. As adviced, I use OE/ signals to control leds drivers. Regarding the via in a surface mount pads - I've decided to leave one like that for testing purposes and see how it will go. JLPCB describes specific parameters of such vias, so it feels like common practice.
gilhad wrote:
About the NC pin - AVR/ATMEGA/Arduino boots with all pins in INPUT state - that means high rezistance - so if you connect it to Arduino and leave it such for 65C02, it should be OK, as there would be effectively connected just the short wire. And for '816 you can drive it yourself. But I would add a jumper, just to set, which CPU is inserted, so Teensy could read it after boot and set everything acordingly.
Good idea about the jumper, but I have no single pin left on my Teensy to read the configuration, so I'm going to leave it to the software - one would need to enable either '816 or '02 version on that level. Perhaps for futer iteration of the project I should move from parallel access of address/data lines to some fast serial shift registers. That feels like an out-of-topic question for this post, but curious whether you have some experience with it.
gilhad wrote:
For Black&White in KiCad is easy to make B&W scheme ( (Preferencies / Preferencies (Ctrl+,) / Schematic Editor / Colors - click Theme and select Black & White, OK - or select New Theme and customize it) You can then use the theme only for printing, or switch it with default on your will. (On my computer it was saved into /home/gilhad/.config/kicad/7.0/colors directory, on yours it should be something similar)
Thanks for the advice. For this project I've been using EasyCad and its configuration options are limitred comparing to KiCad (that includes color settings). I quite like EasyCad due to its great library of components and footprints, but it annoys me massively due to the lack of support for active-on-low names (with overline).