Strange Happenings (ACA500Plus)

SpaceFlightOrange · Jan 31st 2021

So, this is strange.

I was booted into Workbench 3.1.4 on the CF card with the 3.1.4 image mapped in and i ran "The Emulator" (An old BBC Micro Emulator - This is really a 1.3 era piece of software). I pressed a key trying to reset the emulator when the tv signal disappeared (the Tv no longer detected a signal from the SCART interface) and a weird, almost buzzing noise was coming from the TV speakers.

ACA started showing 8.8 on the dismo and the dismo light was bright white. I reset and the machine booted but the dismo wouldnt clear, and when i went into the ACA menu the dismo was showing weird things, essentially a single segment on each digit was lit. I powered off an on, and it booted straight into the ACA menu, which it shouldn’t, because i have it configured to autobooot into expert profile #1, and the RTC on my trapdoor expansion had reset!!!

The main Config (f8) was fine, but my main expert profile (#1) had been wiped!! My other 2 profiles were intact

I removed the ACA and started the machine up and rant AmigaTestKit. All seems fine though that confirmed the clock had reset.

I've re-inserted the ACA and reconfigured my profile and everything seems fine now, but I was sweating for a while there! is this anything i should be worried about?

Jens · Feb 1st 2021

Quote from SpaceFlightOrange

is this anything i should be worried about?

It looks like the crashing software has hit a few DisMo registers, as you confirmed that funny things were shown on the display. You have to know that the non-volatile storage for profiles is in the DisMo, so it's possible (though unlikely) that a byte has been changed in the profile storage space.

The description of the monitor losing sync and a buzzing noise audible really points to the software totally going bonkers, writing to many memory/IO locations in a row. Since this normally happend in ascending order, I usually arrange my registers and procedures in a way that they require backwards-writing in order to do "destructive" things, but you can never exclude software to do really strange things when it crashes.

Long story short: Even if this is reproducable, I'd turn to the author of the BBC Micro emulator rather than attempting to keep it from happening on the ACA500plus side.