Author Topic: [SOLVED] Finding pinout of ASIC  (Read 4015 times)

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Offline tyguy2

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[SOLVED] Finding pinout of ASIC
« on: February 17, 2016, 05:12:16 pm »
I've got a chip that I need help identifying. The label on the chip reads SEGA 315-5682. It looks like the chip attached, but has a different label. Can anyone find a pinout?
« Last Edit: February 20, 2016, 09:04:40 pm by tyguy2 »
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Offline Skimask

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Re: Finding pinout of ASIC
« Reply #1 on: February 17, 2016, 07:18:44 pm »
Ya, that's legible... |O
I didn't take it apart.
I turned it on.

The only stupid question is, well, most of them...

Save a fuse...Blow an electrician.
 

Offline tyguy2

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Re: Finding pinout of ASIC
« Reply #2 on: February 17, 2016, 07:37:00 pm »
Hmm, I'll try and get a better pic of it tonight.
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Offline Kilrah

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Re: Finding pinout of ASIC
« Reply #3 on: February 17, 2016, 07:57:27 pm »
Maybe say what device it comes from?
 

Offline tyguy2

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Re: Finding pinout of ASIC
« Reply #4 on: February 17, 2016, 08:00:08 pm »
Whoops, sorry. This is coming from a Game Gear hand held (see this thread https://www.eevblog.com/forum/projects/converting-rgb-scart-to-vga/). It's the main processor unit. Specifically, I'm trying to find Pins D0 - D3, the clock, csync, and hlatch.
« Last Edit: February 17, 2016, 08:03:10 pm by tyguy2 »
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Offline Kilrah

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Re: Finding pinout of ASIC
« Reply #5 on: February 17, 2016, 08:08:38 pm »
Seems to be easy to find schematics of the GG but not of that version (VA4). Maybe the VA1 / first single chip version is "close enough" if you get lucky...
 

Offline tyguy2

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Re: Finding pinout of ASIC
« Reply #6 on: February 17, 2016, 08:10:32 pm »
The problem is that they basically changed the resistor layout in this version I'm borrowing a V1 from a friend to try and cross reference, but it doesn't seem to be the same.
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Offline McBryce

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Re: Finding pinout of ASIC
« Reply #7 on: February 17, 2016, 09:22:55 pm »
The info on this site might help you: http://members.optusnet.com.au/eviltim/ggrgb/ggrgb.html

McBryce.
 

Offline tyguy2

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Re: Finding pinout of ASIC
« Reply #8 on: February 17, 2016, 11:50:29 pm »
Whoops, sorry. This is coming from a Game Gear hand held (see this thread https://www.eevblog.com/forum/projects/converting-rgb-scart-to-vga/). It's the main processor unit. Specifically, I'm trying to find Pins D0 - D3, the clock, csync, and hlatch.

Yeah, I mentioned that in this thread.
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Offline pmichel

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Re: Finding pinout of ASIC
« Reply #9 on: February 18, 2016, 04:28:25 pm »
Found a clearer picture and a couple of other sites with some more information. Like Kilrah said, it's mostly for the other versions. If the LCD pads, connectors, or test points are the same you may be able to work backwards from them.
http://www.smspower.org/forums/2539-GameGearTV
https://console5.com/wiki/Game_Gear
 

Offline Kilrah

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Re: Finding pinout of ASIC
« Reply #10 on: February 18, 2016, 07:58:52 pm »
Time to whip the scope out and look for signals that look appropriate I guess.
 

Offline tyguy2

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Re: Finding pinout of ASIC
« Reply #11 on: February 18, 2016, 08:02:20 pm »
The problem is that I don't have anything to compare the signal to, and my scope is only 10 mhz, so I couldn't see the 32 mhz clock if I tried.
« Last Edit: February 18, 2016, 08:09:22 pm by tyguy2 »
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Offline tyguy2

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Re: Finding pinout of ASIC
« Reply #12 on: February 18, 2016, 08:15:21 pm »
Here is a picture of my exact chip
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Offline McBryce

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Re: Finding pinout of ASIC
« Reply #13 on: February 18, 2016, 08:22:55 pm »
The clock signal can be found without a scope, just by following the traces from the crystal. The CSync should be easily viewable on even a 10Mhz scope.

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Offline tyguy2

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Re: Finding pinout of ASIC
« Reply #14 on: February 18, 2016, 08:36:01 pm »
Ok, I followed the traces, I think I found the clock pin. The screen freezes whenever I connect my probe to it, then un-freezes when I disconnect. Should I attach my clock pin directly to the crystal, or elsewhere?
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Offline McBryce

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Re: Finding pinout of ASIC
« Reply #15 on: February 18, 2016, 09:35:27 pm »
I don't know the circuit, but if the clock is buffered with something like a 74HCU04 or whatever, then I'd take the clock directly at the output of the gate.

What probe is stopping the clock? A properly setup 10:1 passive scope probe shouldn't knock the clock out.

McBryce.
 

Offline tyguy2

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Re: Finding pinout of ASIC
« Reply #16 on: February 19, 2016, 06:15:26 pm »
I finally got the other board from my friend, I'll post my find later tonight on if the signals are a match. :-+
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Offline tyguy2

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Re: Finding pinout of ASIC
« Reply #17 on: February 20, 2016, 09:04:02 pm »
Alright, I figured out the Clock signal (and finished the project). It's labeled as C27. :-+
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