I'm curious about this. So I got this Xellent30S that I want to get the most out of and I found this JP site where it says he upgraded it with a 40MHZ processor (68030RC40)
http://web.kyoto-inet.or.jp/people/m-ito/netbsd/netbsd.html (http://web.kyoto-inet.or.jp/people/m-ito/netbsd/netbsd.html)
Of course this is for NetBSD, but I have no interest in that.
According to the Oh! X 2000 on the page you need to get rid of pins X (to boot X-Windows, which I might be interested in..but defiantly not needed), D and pull up + connect 4.7OHM to MMUDIS. Now I'm not sure if those last 2 are needed in order to boot a 40 mhz version of the processor or just part of the Net BSD junk.
Has anyone tried this? The crystal oscillator on the board only connects to the FPU, so it wouldn't make sense to change that. Any thoughts on this?
ah damn that's cool! I wish i could help but i can't even get my x68000 to boot with my xellent30s installed so i think the board may be broken somewhere. I'll try to mess with it over the break.
may i ask where you found yours?
Someone living in Japan had an extra one and sold it to me.
Hi Hyperneogeo !
The mod looks very simple and maybe you could even get away with only inserting the 40Mhz processor. I think that the MMUDIS mod could only apply to NetBSD and is not required in normal every day use. Try disconnecting FC2 if a simple CPU swap does not do the trick. The next step, if there are still trouble, would be to disconnect the NC pins.
Disconnect the X (FC2) pin from MC68030 socket if you want to use the X Window System
Disconnect the unneeded D (NC - not connected) pins from MC68030 socket
MMUDIS - solder a 4.7k ohm resistor between V (Vcc - power supply) and M (MMUDIS). This one is not entirely clear. Does the MMUDIS pin needs to be separated from the socket or not ?
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o o o o D o o o o
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o o o D D V o M
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FC0–FC2 (Function Codes) - 3-bit function code used to identify the address space of each bus
cycle.
MMUDIS - The MMU supports virtual memory systems by translating logical addresses to physical ad-
dresses using translation tables stored in memory. The MMU stores address mappings in
an address translation cache (ATC) that contains the most recently used translations. When
the ATC contains the address for a bus cycle requested by the CPU, a translation table
search is not performed. Translations Can Be Disabled with External MMUDIS
Signal
Keep the scene alive !
Eidis
Very interesting. Thanks for the additional information. I'm going to try to track down a 40 mhz version and see what it does.
Edit: Also I think he might mean you need to connect the 4.7k OHM resistor to the MMUDIS pin while leaving it in the slot. That would make more sense than taking the pin out imo.
Edit agin: http://www.geocities.co.jp/SiliconValley-SanJose/6068/x68/ace.html (http://www.geocities.co.jp/SiliconValley-SanJose/6068/x68/ace.html) Another site with a guy fiddling with the Xellent30S and putting in a 50 mhz one.
I cant imagine any games that would take advantage of a 40MHz proc and still run correctly. On the other hand you might be able to run win95 better lol
Quote from: Opethian on December 16, 2014, 01:01:21 AM
I cant imagine any games that would take advantage of a 40MHz proc and still run correctly. On the other hand you might be able to run win95 better lol
Purely curiosity heh...might be able to run Road Blaster at 10 FPS!!!!
Hi Opethian !
Could you please provide more info on Win95 for the X68000 ?
Keep the scene alive !
Eidis
Quote from: eidis on December 16, 2014, 04:44:21 PM
Hi Opethian !
Could you please provide more info on Win95 for the X68000 ?
Keep the scene alive !
Eidis
I think he got confused with CPU upgrades for the FM Towns. ;D
ah yes sorry it was Towns that got the Win 95
I guess the only shell X68000 was SX and KO then?
There were a few other operating systems such as OS-9, but that's only for the nerd elite.
Okay I went ahead and did it and from what I can tell it does jack lol. I removed the pins and soldered the 4.7k ohm to the VCC and the MM (but he mentions that power is already soldered to MM with the other resistor, so I dunno what adding another one does). Maybe this is only for getting Netbsd to work or something..dunno.
Hi Hyperneogeo !
QuoteMaybe this is only for getting Netbsd to work or something..dunno.
That is correct. This hack disables the 68030 MMU and in this case is only required for running NetBSD.
More info on the MMU can be found here:
Memory management unit
http://en.wikipedia.org/wiki/Memory_management_unit (http://en.wikipedia.org/wiki/Memory_management_unit)
Keep the scene alive !
Eidis
If an Xellent30 has been modded to work with NetBSD, will it still work as intended with regular X68K games? There is one currently on YAJ, but it looks like there is a resistor soldered on the back of it and it mentions NetBSD "remodelling". Some of the instructions above mention removing pins, so can anyone confirm if this is detrimental for normal use? Thanks!
you can always take it off.
I can only say this from emulation experience, but no, it doesn't seem to matter if your 030 is modded for NetBSD. If all you're doing is playing games, you don't need an 030 anyway. Almost no games benefit from it.