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Jason Starr
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Little Update
Post Posted: Mon Jan 17, 2000 1:42 am
Well yesterday I took my girlfriends Sega Master System 2 apart to take a look at the circuit board. I made a rough sketch of all the IC's and other "important" stuff which I could see. THere where 10 IC's that I could see and I made some educated guess's as to which chips did what but I want to know for sure which is which. From a previous post on this board I heard IC2 was the Alex Kidd rom, IC1 is obviously the z80, IC3 is 8k ram? IC4 and IC5 i am not sure what these are... maybe the GFX chip and sound? IC6 and IC7 I think is more RAM. IC8 + 9 Im not sure. Could anyone describe to me what all these IC's are used for, just for some general knowledge. I'm also wondering if anyone has any circuit board scans of the Master System, both the SMS1 and SMS2. I took a look at a few cartridge's to, nothing too spectacular to report. Zoop, i think you are right in saying how I should document it after I have written a SMS emulator, but I also dont want to lose my "newbieness" and become too technical so that people in the future who are like me now, wont be able to understand it as much. Also thanks to Jose for your info, it puts a lot into perspective. How many other people on this board are starting new emulators and are relatively new to it? This isnt just exclusive to SMS emulators but all... Well thats all for today...

-Jason Starr-
 
  • Joined: 28 Sep 1999
  • Posts: 1156
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Post Posted: Tue Jan 18, 2000 4:57 pm

Here are the SMS2 components:

IC1: Z80
IC2: ROM (Alex Kidd or whatever game is built-in)
IC3: RAM (8K)
IC4: Unknown, most of the IC5 and controller pins go to it. Might be for address decoding and port stuff
IC5: Most likely a multifunction chip, definetly contains the VDP
IC6: 8K of RAM for the VDP
IC7: 8K of RAM for the VDP
IC9: RGB to composite video encoder, I think. Nothing terribly important. There's a datasheet for a work-alike part at Sony's website. The Genesis also has this same part.

IC4 or IC5 probably has the PSG and other miscellaneous logic in it.

They really simplified the board layout for the SMS2, the old
version has more chips that do the same thing as this one.

IMHO you don't need to know any of this to write an emulator. :)


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Limbs a Flyin'
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Post Posted: Wed Jan 19, 2000 8:37 am

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> IC9: RGB to composite video encoder, I think. Nothing terribly important. There's a datasheet for a work-alike part at Sony's website. The Genesis also has this same part.

aha! so i can hack in support for rgb out instead of crappy RF!

rgb out on consoles works great on an *old* NEC Multisync (low refresh like when using an Amiga monitor, except with low dotpitch)
 
  • Joined: 12 Jul 1999
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Then what is IC8? *nt*
Post Posted: Thu Jan 20, 2000 3:52 pm
Quote
>
> Here are the SMS2 components:

> IC1: Z80
> IC2: ROM (Alex Kidd or whatever game is built-in)
> IC3: RAM (8K)
> IC4: Unknown, most of the IC5 and controller pins go to it. Might be for address decoding and port stuff
> IC5: Most likely a multifunction chip, definetly contains the VDP
> IC6: 8K of RAM for the VDP
> IC7: 8K of RAM for the VDP
> IC9: RGB to composite video encoder, I think. Nothing terribly important. There's a datasheet for a work-alike part at Sony's website. The Genesis also has this same part.

> IC4 or IC5 probably has the PSG and other miscellaneous logic in it.

> They really simplified the board layout for the SMS2, the old
> version has more chips that do the same thing as this one.

> IMHO you don't need to know any of this to write an emulator. :)
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