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NFG Forums => SIG X68000 => Topic started by: trixster on March 29, 2020, 11:32:44 PM

Title: XVI 16mhz mode and Geograph Seal crash
Post by: trixster on March 29, 2020, 11:32:44 PM
Hi,

I have an XVI with 2MB PIO-6834-2/4M-1 ram board (jumpers set to 0 0 0 0) which works great in all respects except with Geograph Seal.

With the XVI set to 16Mhz I cannot get GS to run with switch.x set to 4096KB, either running from SCSI2SD or from floppy disks. I always get a Bus Error or Address Error once trying to start from the game menu.

If I set the machine to 10Mhz then the game plays fine either from scsi2sd or floppies with switch.x at 4096KB.

But if I set switch.x to 2048KB I can then successfully play the game at both 16 and 10Mhz.

So what is it about 16Mhz and my ram expansion that GS does not like?

I have run MTEST to confirm the memory on the PIO is fine, and in all other respects the machine operates great at 16Mhz....
Title: Re: XVI 16mhz mode and Geograph Seal crash
Post by: SuperDeadite on March 30, 2020, 11:52:17 PM
Geograph is one of the very few games that takes full advantage of the XVI's faster internal RAM.  The i/o slots are slower.  You need to use the mobo's internal RAM expansion for geograph to function properly at 16mhz.  99% of the library does not care about the speed issue though.
Title: Re: XVI 16mhz mode and Geograph Seal crash
Post by: trixster on March 31, 2020, 06:47:35 AM
Thanks for the info, that's interesting. I guess I'll need to check yahoo jp for an internal memory upgrade then.