Recent content by ClausB

Excellent YT series:

Looks like it might be a circuit to make upper RAM write-only, to simulate ROM and defeat cartridge copy protection.

Tetris sometimes shows screen corruption near the top when a new piece appears, though it does not crash. Even though it fits comfortably in RAM, I wondered whether it was addressing more than 1K, so I added a trap to memwrite() and found that it does use a few bytes in pages 7 and 8 for temp...

Interesting video. That first bit sounds much like an Atari 810 disk drive loading. The Atari's audio chip also runs the serial disk I/O and so makes audible noise. Coincidentally, Atari used the PDP-11 for the 800's OS development.

Got the VIP ROM from Emma02. Working so far. Need to test more CHIP-8 programs next, or maybe write one.

I was unfairly critical above of the ROM. I was expecting the VIP monitor but what is provided is the Elf monitor IDIOT instead. Apologies. I'll try adding the VIP ROM...

Thanks, @Oscar, I'm enjoying your kit. In the 70s I saw BYTE ads for Elfs and the VIP and wondered about them. Now I can play!

Oops that wasn't the problem Tetris doesn't use Fx. I had to improve my keypad logic to get it to work. Now it does work but the Fx problem remains. How much fun is it playing Tetris though a magnifying glass?

I did so and available program RAM is now over 600 bytes. I loaded the Tetris game and it runs but doesn't respond to keypresses. Looks like the CHIP-8 keypad instructions Ex do work but Fx does not. Turns out that the Monitor ROM was gutted worse than I thought. Not only the character set but...

4. Patching the game was not useful in the long run, so I added the timer logic to scanKeys() instead. Next I'd like to move pages 0 and 1 to Uno ROM to free up RAM for longer CHIP-8 games.

You might also want this port of T80-FS1: Thread 'FS1 for Exidy Sorcerer' https://forum.vcfed.org/index.php?threads/fs1-for-exidy-sorcerer.1237688/

Nice work! This long-running thread had my project history. You are welcome to post there. Post in thread 'Exidy Sorcerer II Questions' https://forum.vcfed.org/index.php?threads/exidy-sorcerer-ii-questions.49776/post-607415

:)

3. The emulator doesn't reproduce Elf keypad scanning, rather it scans the Uno keys in Arduino code. So flag EF3 never gets set. I had to add some logic to set and clear it in scanKeys(). 4. The emulator does not maintain the timer, probably because the interrupt is not supported. I patched the...

Nice. Similar to what I did using the UART: https://forum.pjrc.com/threads/55633-posted-Tape-Simulator-for-Exidy-Sorcerer What command must you enter to load from the parallel port?