Z80 Computer - Part 15 Testing the Keyboard

[@zxborg9681]

Wow, that keyboard looks great. I built my first z80 board in 1985 and had a little 20 pin keyboard I pulled from a calculator, just enough for hex digits plus a NEXT, WRITE, GO, and some other button (I forget). Was simple enough I could enter programs and run them out of a sub-256 byte boot code in an EPROM. I remember writing a very similar keyboard row/column scanner just like you show at the start. Was thinking for your keyboard you could write a little test program kind of like the HP calculators (like the 15C or 32S) use in their secret selftest modes, you just hit every key from left to right top to bottom and the program figures out if it saw all the right codes and finally displays "OK" at the end. Could implement using a table of expected results or a checksum I guess. Looks like great fun on your end and a trip down memory lane on mine. Thanks for sharing!

[@CarCinCal]

That keyboard is incredible - well done!

[@SteveRaynerMakes]

thanks

[@mikehibbett3301]

Lovely keyboard. I built Z80 systems in the 1980s, but they were embedded systems so never thought to add a keyboard interface. Keep it up!

[@SteveRaynerMakes]

Thank you. this project is so much fun to play with. When I had a Z80 computer back in the 80s I did not have access to any electronics. All I could do is read about this stuff in books and dream about making things. Now I can do the things I wanted to do as a child. I've got a long way to go, and a lot of learning to do, but I'm having fun.

[@mikehibbett3301]

@@SteveRaynerMakes My first computer was a 6502 system (Acorn System 1) but I did a lot of assembly development in z80 on the ZX81 later on. Writing assembly on paper, and having to re-write it on paper again when I added one instruction was a pain, but it was more fun that watching TV :) That project got me a place in university which was a bonus.

[@SteveRaynerMakes]

@@mikehibbett3301 oh yes, i can remember spending hours writing assemble code out on paper. Manually looking up the instructions and cross referencing the hex codes. Type the hex codes in, save them, run the program, watch it crash, scratch my head and repeat. To this day when I write any program code I always save the code before trying to run it, because I was so used the whole computer crashing and losing everything that was in memory.

[@mikehibbett3301]

@@SteveRaynerMakes lol. We must be a similar age. They were great times, I remember bringing my computer into school, and it was the first one they had seen. Happy days

[@user-fi5hr2ig4s]

just was watching episode 14, and saw that episode 15 released

[@user-ws4nz8fu6z]

Это круто! :)