I found a rather peculiar issue when it comes with dealing with BBS Telnet software. In 40 column mode I am often seeing RS-232 breaks in teh telnet window long but these do not appear in 80 column mode.
Is there something about 40 column mode that impacts the user port?
Fri, 2019-03-08 09:56
#1
Crashes in 40 columns but none in 80
Hmmmm are you running 80 column mode with the 8502 at 2 MHz or 1 MHz? If you're running at 2 MHz, that may explain why it performs better using 80 columns.
I am assuming it is running at 2mHz as it is in 128 mode. I wasn't aware there was a way to switch between 2mHz and 1mHz without executing the "fast" command.
One way to get to 2 MHz mode is by poke 53296,255 or return to 1 MHz by poke 53296,0 (using BANK 15)
(Assuming you're using a real 128 (not an emulator like VICE), if you see anything other than just solid color on the 40 column screen you're using 1 MHz mode)
Ha. IN 40 column mode I see colored static. Nothing solid.
Yep. Your C128 is using 2 MHz mode when using 80 columns. That is most likely why it performs properly when in 80 col mode but not in 40 col mode (because the processor is in 1 MHz mode). That colored static confirms that it is at 2 MHz without using BASIC's FAST command, but rather POKEing to the aforementioned location to achieve 2 MHz.