Progress

 I haven't written for a few days, however I have been getting somewhere. I have a working emulator that runs on PC (should run on anything) and ESP32. See picture (not great quality) of AD&D Tarmin running on the ESP32 board.

I've tweaked the cassette format slightly, just by allowing CAQ files (effectively dumps of what is sent to/from the cassette port to be concatenated.

Some hacks to the ROM have removed a lot of annoying "press any key" type messages and you can now just CLOAD "<whatever>". CLOAD without a filename will load a directory a bit like on the CBM machines.

This also works for cartridges so you can CLOAD "TARMIN" and it will load the cartridge, detect it is a cartridge and then reset the computer automatically.

Also gone are the irritating beeps on key press, the start up press any key screen, the limitation on PEEK and POKE and the Printing is disabled, for now anyway. 

I had hoped to produce a quicker version, something that you can turn on a high speed version. This is easy enough for the PC, but the ESP32 appears to be running near flat out. Doing an empty 10,000 for/next loop takes about 10s or so, I've got that down to just under 8 after a bit of optimising. Not bad, but I'd hoped for closer to 6Mhz equivalent. 

Sound works, but it doesn't do any fancy PCM tricks, it just averages out the pitch over a frame, which gives it a slightly static sound effect. Might fix this, difficult to know. I want it to be runnable on a TTGO-VGA Board (the one pictured) which is about £10 or so and Fabgl compatible out of the box, so piling in too much will take from that.

There's a link to the github on the top left (probably)