MiSTer FPGA Forum

Hi all,

I've had the ao486 core hang/freeze on me a few times, it seems like regardless of how well a game is running, eventually it'll hang. I'm using the Flynnsbit DOS98 Boot VHD modified to allow me to use my own D: VHD, and I've mainly been using the HIRAM option at 90mhz.

It's happened on Sierra adventure games, it happened on Companions of Xanth (Floppy AND CD), and a couple other games. The most alarming one was Where in Time is Carmen Sandiego, which was running off floppy (A:) and which is hardly taxing on the core.

I have a 128mb SDRAM in an aluminum passive case from Misteraddons, so I don't think it's a heat issue, it hasn't even been warm.

Wondering if it could be the HIRAM setting? Or maybe if I don't downclock the core speed for the game, it happens inevitably? Or maybe the core just still has some stability issues? Appreciate any tips!

To be clear, the MiSTer isn't hanging; I can still bring up the WIN + W12 menu, but I just have no choice but to reboot, and it makes me feel like maybe I can't actually play anything carefree for fear of a looming hang.

How hot is the FPGA itself getting? I had issues early on with AO486 that have been resolved by putting a small fan on top of the FPGA heatsink. It could be in my head, but it crashes far less often now. Mine was getting hot enough to burn the tip of my finger in just a second or two.

I highly doubt it’s temperature related considering it has happened within the first few minutes of starting the system up and running a game.

Is there a good stress test, maybe the most demanding functional core, I could play for 30 min plus to rule out whether it's temp or not?

Cooling *is* recommended when using the ao486 core:

https://github.com/MiSTer-devel/Main_Mi ... #3-cooling

Some large cores such as ao486 and Minimig are sensitive to FPGA chip temperature and become unstable if it becomes too hot. So active cooling, in addition to passive cooling, is recommended for stability.

Cooling is not the problem here, i have the same freezes with Xanth.

And it's not a complete freeze, the game goes on after an ingame event is triggered.
In the case of Xanth it's the periodic ringing of the kitchen telephone.

After the internal ringing event is triggered, the game runs fine until the next user action (for example "open door") --> Game "freezes" again until the next ringing event and so on ...

I'm having these freezing troubles in ao486 games also (for many games in the Flynn Top 300 DOS pack). Hopefully it'll be fixed in a patch at some point. Secret of Monkey Island just locks up at practically every new cutscene (can still access the MiSTer OSD, etc... and even the MIDI sound keeps playing). Same thing with Prince of Persia 2... I get to the second level and it locks up within 10 seconds, every time, no matter which memory manager I use (and again, OSD remains accessible and MIDI sound continues). Cooling is not my issue.... my MiSTer is fully kitted out.

I wonder if it’s sound driver related. In Xanth, yes it seemed to always freeze when something was supposed to load. I may go back and play a bit more of it with adlib music only, just to see if it's stable. But it's happened with every memory option, and it's happened in different games... it seems really weird to me it would just be a CPU emulation issue, though I’m certainly no expert on how easily it can go wrong. Amazing core still, I just finished Xanth for the first time in many years and loved the experience again. But would be nice if I wasn’t expecting games to inexplicably hang.

I just touched the top of the aluminum case and it’s BARELY warm. So either it’s not dissipating enough and it’s heating up in there, or it’s absorbing everything there is and it’s just not that hot.

Monkey Island is freezing for me too.

I don't think it's sound related as it's frozen on me with Munt and also using a MT32pi.

Frozen in 3 different places, so seems random.

simon the sorcerer intro is freezing too.

Discworld has been randomly freezing for me. I have yet to try any other games,

Have you tried using Soundblaster FM sound instead of General Midi/Soundcanvas? This happened to me back in the 90's when using real hardware. The synth instruments freezes sometimes using General Midi, it does not really matter if you are using internal synth like Mute or an external MT32pi.

Anyone able to resolve the random freezing? I’m seeing this with Monkey Island and Prince of Persia.

I am also seeing this with Monkey Island and Space Quest 3.
So I am asking myself if this might be sound related, I am using MIDI for Mister with real MT32 hardware. What did you guys use when the games froze?

After updating to latest AO486 and MT-32pi firmware the notes hanging when using MT-32 has been resolved for me on both Prince of Persia and The Secret of Monkey Island.