MiSTer FPGA Forum

I've had a problem with the C64 core for while now. When i load the core it just gives me a black screen, but the menus work as expected. Until recently running the C64 core would also really screw up the mister making every other core (even the menu) display horribly corrupt graphics and failing in pretty fantastic/strange ways. The corruption even persistent after power cycling the mister. I would have to power it off and let it be off a while for it to return to normal. This corruption part went away semi-recently. I've tested multiple loadable kernels and the standard. I have also tested multiple releases of the core.

Every other core on my mister seems to run fine and my 128MB RAM passes at 142mhz and works fine in Jotego's CPS 1.5 core (even the versions that a lot of people seemed to have issues with).

I'm not totally sure, but the issues might have started after installed the 128MB RAM module and i have since misplaced my 32MB RAM module. Would there be a reason that only the C64 core might have issues with my 128MB RAM? Is there another core that is really sensitive to RAM issues that i could test?

Any suggestions are welcome.

maybe a corrupted cluster where the core resides?
try a reformat or different sd card and see if the problem persists?

I tried a new SD card earlier today. Only Mister, menu.rbf and the C64 core on there. Same issue :/

As far as I know the C64 core does not like to be started from another core. For C64 I always do a hard reset and load the C64 directly from the menu.

I pretty much always do a cold boot when switching between cores especially when trying the C64 core.

odd, if other cores work just fine and memtest has no issues.
have you checked the boot rom?

Sometimes I have the same issue. Than it helps starting the vic20 core first and then C64 one don't know why

I have the same issue. A black screen on launching the C64 Core. My memory test shows my 128 mb ram expansion is working correctly. It passes at 140.

I have tried both with and without the boot.rom which I created from the roms in VICE. I have replaced the rbr with ones downloaded from the repository all are dated 26th Feb 2021.

I tried launching the Vic 20 core first and no joy there.

Its very confusing. It surely cant be using that much RAM as its just a 64k computer.

Any ideas ?

Hello

Try with my files

I tried the boot.rom with the same result. Just a black screen. F12 brings up the menus but the C65 just doesnt boot. Its very strange.

Thanks for the response though.

Maybe try this as a last ditch effort.
I've modified this a little so you don't have to set up the c64 core just install and run it without trying to configure anything.

I've written this to a SD card myself and it expands and works perfectly.

1) FORMAT your "blank / spare" SD card with THIS

https://www.sdcard.org/downloads/formatter/

2) Write the image you downloaded in 1) to the SD card with THIS

https://sourceforge.net/projects/win32diskimager/

3) Insert SD card into Mister, Power on and wait until it uncompresses and restarts.

On restart you will see the C64 core, just run it.

Thanks for that. I burnt it to a new spare SD card. It installed and the only core was the C64 as expected. It however boots to a black screen when I start the core.

Its a mystery to me why this is happening, but I guess I will just have to do without a C64 on the Mister for the time being

Tried various old core versions and no luck. Are there debug logs showing whats happening ?

The files I am using for the C64 and my Mister.ini. boot.rom is only the freely available combined rom from Vice.

Give this rom file a try.
I have confirmed that it works

https://misterfpga.org/viewtopic.php?f=12&t=1764

Thanks I tried that and the same issues.

Tontonkaloun has been trying to help via Pm and the files that dont work for me work fine for him.

I just ran the Bad Apple NeoGeo Demo without issue so I know my SDRam is fine

I am outputting to a 55 inch LG OLED so nothing outrageous there and every other core seems to work without issue. Its just a mystery

Did you try on a different monitor?

Thats about the only thing left to try. I will have to move the mister from its nest and connect it to my various monitors

Are you outputting to HDMI or some other device?
I've only ever used HDMI and it works fine but I can't see any mention above about your display.

I'm not trying to suggest anything, just fact finding in order to advise you better.

The only other "last ditch" piece of knowledge I can pass one is that when I bought my first RAM module (32mb) It didn't work at all with my MiSTer setup. I contacted the supplier who told me about seeing faulty DE10-Nano boards previously.

I contacted my supplier of the DE10 board and they sent me a replacement. The RAM module worked perfectly (and still does to this day) .

Not sure if this is relevant but it's something that stuck in my mind.

It's an issue with the core. It happens to everyone.

I am outputing via HDMI.

I think I shall just sit back and wait for the Core to Evolve. I got it for free and the Mister provides me a whole world of Cores. So whilst its a shame I cant use it for the C64 I can use it for many other systems.

After last update ( today ) the C64 core goes black. OSD Works but no C64 Screen nor prompt on screen.
Edit: I realised that now rom is located in /C64/bootrom/c64.rom

Now works fine !

So did you create a bootrom directory in the /games/C64 directory and then put a rom renamed to c64.rom ?

I tried that but sadly it didnt fix it for me. Just the black screen with a working OSD

rhester72 wrote: ↑Wed Mar 03, 2021 11:49 pm It's an issue with the core. It happens to everyone.

So far it never happened to me.

You are lucky then. Its the only core that I cant get to work.

ron wrote: ↑Mon Mar 15, 2021 4:56 pm After last update ( today ) the C64 core goes black. OSD Works but no C64 Screen nor prompt on screen.
Edit: I realised that now rom is located in /C64/bootrom/c64.rom

Now works fine !

Is this information available somewhere? The Wiki only says boot.rom in the games/C64 folder.

Why are you trying to use a boot.rom? The core does need a boot.rom to work and using one is unlikely to solve your problem. Try to make it work without a boot.rom first.

I tried that way at first, that failed so I went into the boot.rom path and thats failed too. The core menu works fine. I can see the video mode being switched too because it displays the video mode and then black screen.

Did this core ever worked on your MISTer? Did you try with a different monitor?