Z80-Frequency-counter-ZX-spectrum
This is a frequency counter in the ZX Spectrum 48k(Harlequin). All code is carefully timed to run for one second, during it it counts the rising edges on the EAR port(bit6 of port 254). HL counts the pulses BC is a dec counter responsible for the one second total time. Initially it did not work, then I look at the harlequin schematic and saw what data line the EAR was connected This idea dates back to the early 90's when I bought a ZX Spectrum +3. I had a manual with the assembler codes and timings, and I kind did something like this, I had no signal generator(still don't thats a online signal generator) so who knows :) Back then there was no internet, I must been 16 or 17 years old. I bought the harlequin and soldered (1093 solder joints) only so I could recreate this code. https://github.com/titojff/Z80-Frequency-counter-ZX-spectrum/tree/main zasm - z80 online assembler The store where I bought the kit: https://www.bytedelight.com/
