Blank screen when I load the MegaCD core

[Thad]

Hi,

This is similar to a problem I'm having with the NeoGeo core. Sorry for another post repeating a lot of the same information, but even though it's the same symptom I'm not sure if it's the same cause. I suspect a BIOS issue but I don't know for sure that's what's causing it.

I haven't been able to get the MegaCD core to boot at all. I have the 128MB SDRAM add-on and the IO board with the generic fan (in case it helps there's more info on my setup in the thread I posted yesterday).

When I try to boot the core, I get a completely blank screen and no inputs seem to work, including the reset button on the IO board. (The Linux environment is still running; I'm able to ssh into it.)

I suspect this may be an issue with the BIOS, because the same thing happened with the GBA core, and resolved itself when I added a boot.rom file.

I've tried several different BIOS files. Here are a few I've tested (copied to games/MegaCD, renamed to boot.rom) and their md5sums:

Code: Select all

683a8a9e273662561172468dfa2858eb  [BIOS] Mega-CD 2 (Japan) (v2.00C).md
310a9081d2edf2d316ab38813136725e  [BIOS] Sega CD 2 (USA) (v2.00).md
854b9150240a198070150e4566ae1290  [BIOS] Sega CD 2 (USA) (v2.00W).md
ecc837c31d77b774c6e27e38f828aa9a  [BIOS] Sega CD 2 (USA) (v2.11X).md

Any ideas or suggestions? Again, I don't know for sure that this is a BIOS issue, or that it has anything to do with the similar issue I'm having with the NeoGeo core; those are just guesses. If anybody could point me in the right direction, that would be much appreciated; TIA.

[RuBEn]

Hi, i think i have the same problem and it's been driving me nuts, mainly because the megacd core was the main reason that made me buy a MiSTer.

Adding to this, i've tested a lot of bios, stock and region-free, and it keeps frozen or flashing at the bios screen with no response. With some portable system bios, like the cdx, i get a message stating it doesn't have enough power.

I've tried different SD cards, controllers, no-ram... without success.

Although he neo-geo core runs fine for me, the PC-Engine CD gave me similar problems but i solved it by formatting a new SD card, but the Mega-CD problem persists.

I am using only the DE10-Nano, without external boards, and a 128Mb Ram.

[rickdangerous]

@RuBen

Humm, that ram sounds an incompatible XXS from Antonio. Send me details, me or Antonio can fix that.

[RuBEn]

In my case, you're right. i use a 128 XXSV ram from Antonio and i read some time ago in the telegram group about the faulty rams, but i've tried without the ram module and i get the same problem ¿? Maybe that excludes the ram? or not?

[rickdangerous]

@RuBen

I produce all kind of ram, including XXS, that modules don’t work in all fpga boards.

Contact me directly that I service that for you for free. I remove chips and put in a original board. You’re in Spain?

[rickdangerous]

Without ram the MegaCD don’t work, need at least 32Mb SDRAM.

[Thad]

I tried the CDX BIOS to see if it gives me the same error as RuBEn. It doesn't; I just get the same blank screen as I do with the other BIOSs I've tried.

(In case this tells anyone anything, the md5sum for the CDX BIOS I have is baca1df271d7c11fe50087c0358f4eb5)

ETA: It looks like there's something wrong with the SD card; I tried another one and I'm able to load the BIOS. Thanks for your help.