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Post by FonzieVoltonov on Apr 18, 2005 5:08:18 GMT -5
Hi, I do know that the sega genesis ext port have the possibility to add one VDP (was planned for the segacd but canned for some cost reasons). In fact, i'm making a board and i would like to add one VDP+VRAM (taken off one genesis model1). There is certainely a way to call the vdp cntl and data port using by board (i have 16KB mapping reserved for this)... I saw some shematics of the MD EXT port that confirm the 2nd vdp possibility: www.gamesx.com/cartouts/gennyport.htmBut all the xx/315-5309 remains undocumented... Any idea about the pin to link from the VDP2 to the genesis ext port? Thx Bye Fonzie
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Post by FonzieVoltonov on Apr 18, 2005 5:19:24 GMT -5
Oki, i just saw a md1 mobo and the vdp seems to be very crap to disolder/solder ;D (alreay did soldering like that, was a nightmare).
It doesn't mean i'll give up, should be cool to know how to add another vdp (mixing with another FULL md model first).
Any idea?
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oompa loompa
I AM THE GOVERNATOR
"Git 'Er Dun!"
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Post by oompa loompa on Apr 21, 2005 21:42:39 GMT -5
never knew they made a vdp peripheral =P. there is nothing out there that will support an external vdp, so being me, i wouldn't bother trying to desolder those custom chips because they were made for a specific mapping. if you were to add the exact vdp to that bus, both vdps will conflict
what i would do is add something like a voodoo card instead, and forget sega's vdp =D
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Post by GiGaBiTe on Apr 22, 2005 15:12:05 GMT -5
lol i think the segas bus speed is a BIT slow to use a pci card. pci bus speeds are 33 MHz, the 68000 is 7.xx MHz i dont think that would work out very well unless you desoldered the gpu and made a custom addon card yourself.
but if you were going to use a voodoo, go for the voodoo3 3000. i think theres a pci version, just have to do some digging.
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oompa loompa
I AM THE GOVERNATOR
"Git 'Er Dun!"
Posts: 1,301
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Post by oompa loompa on Apr 27, 2005 16:30:53 GMT -5
bus speeds never stopped rome. strap on a pentium coprocessor will get pci to work =)
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Post by GiGaBiTe on May 2, 2005 18:18:07 GMT -5
o.O a pentium processor on a sega? that would be insanely complex to build, the pentium has like 208 pins...
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oompa loompa
I AM THE GOVERNATOR
"Git 'Er Dun!"
Posts: 1,301
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Post by oompa loompa on May 2, 2005 23:25:23 GMT -5
it'd be easiest to use a pentium motherboard instead of making one, and put the sega genesis on the pci bus for communications =P. much like the terra drive
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Post by GiGaBiTe on May 4, 2005 2:05:24 GMT -5
then you would have to worry about timing, memory addresses, bus speed. else the memory would go corrupt X.x but i suppose it would be possible like that eisa nindendo
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oompa loompa
I AM THE GOVERNATOR
"Git 'Er Dun!"
Posts: 1,301
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Post by oompa loompa on May 11, 2005 14:27:19 GMT -5
yea, there would need to be an i/o interface rather than a direct bus interface to communicate between each systems
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Post by MaskofDestiny on May 16, 2005 11:29:17 GMT -5
There are some PCI busboards for the Amiga. I don't think there are any for the 68000 based Amiga's though so hacking one of those could be problematic (lowest model supported is the A1200 with it's 68020).
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oompa loompa
I AM THE GOVERNATOR
"Git 'Er Dun!"
Posts: 1,301
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Post by oompa loompa on May 22, 2005 15:07:18 GMT -5
to do this, someone's gotta make their own i/o board with all the pci bridges, or whacha call it, i dunno jack about pci busses
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