315-5433 pinouts?

Charles MacDonald · Post by **Charles MacDonald** » Sun Dec 09, 2012 5:08 pm

Do we have any kind of pinouts for this chip, even partial ones?

I'm curious which pins are for the third I/O port.

Nemesis · Post by **Nemesis** » Wed Dec 12, 2012 10:13 am

I'm not sure that I've ever seen any, and I've never made any myself. I think like most other people I tend to focus on the first hardware version. Revisions are usually just cost cutting measures, and I tend to find them less interesting.

TmEE co.(TM) · Post by **TmEE co.(TM)** » Wed Dec 12, 2012 10:17 am

The pins of all 3 ports are in a row on all the chips, including MD2 ASIC.

ElBarto · Post by **ElBarto** » Wed Jan 09, 2013 7:10 am

http://wiki.megadrive.org/index.php?title=315-5433

Here you go.

Still miss 4/5 pins but ...

notaz · Post by **notaz** » Wed Jan 09, 2013 12:07 pm

I see you have some photos of it, you can crop it from here for another a bit less blurry version:
http://notaz.gp2x.de/img/hw/megadrive_model1.jpg

Chilly Willy · Post by **Chilly Willy** » Wed Jan 09, 2013 7:28 pm

ElBarto wrote:http://wiki.megadrive.org/index.php?title=315-5433

Here you go.

Still miss 4/5 pins but ...

Your list of pins says

A0-A23 M68K Address Bus

Which is a slight goof - it's A1-A23... there is no A0 on the 68000.

Charles MacDonald · Post by **Charles MacDonald** » Thu Jan 10, 2013 12:44 am

Thanks for the pinouts! This is just what I needed.

Very cool to see the unpopulated modem port on that PCB photo, I guess that's one way to cut costs down.

Huge · Post by **Huge** » Sat Jan 12, 2013 2:04 pm

As luck would have it, this chip is one that was photographed by a guy selling photocopies of sega service manuals on ebay.

So, we have an official pinout for this chip.

Pins 69-71 are labeled as test pins on this...

Charles MacDonald · Post by **Charles MacDonald** » Sat Jan 12, 2013 7:36 pm

Ha! What a coincidence -- thanks for pointing this out!