This works great! Thanks gfoot!!

I saw you posted the actual code you're using, which is really helpful as it shows how the hardware looks from the software point of view. See below the algorithm I was suggesting, based on how your hardware seems to work.

It's split into three portions - first ...

Thanks gfoot! I like your idea and I'll give it a try.

I saw you posted the actual code you're using, which is really helpful as it shows how the hardware looks from the software point of view. See below the algorithm I was suggesting, based on how your hardware seems to work.

It's split into ...

The assembly code that I wrote that works fine but it's one note at a time, meaning if you hold down a key and press another while still holding the first key down is hangs on to the first key until you release it. It's pretty good but when trying to play a fast arpeggio it's definitely noticeable ...

Thanks everyone! Lots of ideas to work with. I'll post the schematic soon and if it will help the assembly code (I'm too old and lazy to learn any of the higher languages)

Thanks and your idea of order priority is exactly what I'm trying to achieve! My analog Pratt Read keyboard used the single switch buss which gave the highest key priority. The keybeds I have have the standard dual bubble contacts per key but for now I'm just using only one of the set, later I plan ...

Thanks Barnacle, I'll give that a try


You might think about building some sort of event system, where the keyboard scanning sends key up and key down events to the main generator. That would put your logic into the generator but easily allow you to return to a previous note if e.g. a grace note ...

Thanks White Flame! That's my problem I just want the keyboard to be monophonic right now. I have the 74AS250 16 to 1 multiplexer and a 74LS138 forming an 8 bit key scanner where when a note is down D7 is high. When a key has it's D7 set high the program decodes the address to know which key it is ...

I use Ophis

I have always written my programs for various SBC 6502 projects with Kowalski 6502 and then run the assembler and burn the ROMs.
Unfortunately Kowalski works worse and worse with wine, on my new Linux system it just hangs and crashes.
Which assembler would you recommend - possibly for ...

I built a modular synthesizer years ago and built an analog keyboard for it using a Pratt Read keyframe. I recently decided to update it and use it in my new jazz/fusion band. I found six surplus keybeds that were supposed to be used in new Roland synths but were sold off because of a broken end key ...