I've been looking at the W65C265SXB board again. Just musing, like I do. The W65C265QBX is just too limited.

It seems pretty simple to add a 512K/1MB static RAM to this thing. The CS5 pin does most of the heavy lifting, wire that to the CE pin, and everything else seems to wire up one to one. Am I missing anything there? Beyond perhaps a capacitor near the power on the RAM chip? The MCU does a bunch of decoding internally.

I've also been playing with the EAGLE layout software. I can't say I'm making any headway on that yet, but picking up a few things.

On the W65C265SXB board is that 50 pin connector. Unfortunately, trying to navigate the components of EAGLE for something basic like "connector" is folly. You get half the internet.

So, what specific kind of connectors are on this board? I don't even know the spacing of the pins. I guess "connectors" are attached to "headers"? So, there are "headers" on this board, not connectors. But then what's a compatible connector? And I assume that there might be some "pass through" connector/header thing, so if you were to make a daughter card, you'd have a connector on the bottom, and headers on the top?

Just trying to suss this all out to make the software happy.

Pin headers (or sometimes called "pin strip headers") are a type of connector. 0.100" spacing is most common, but there are others as well, like .156", 2mm (which is approximately .079"), maybe .050", etc.. If you plug cables into them, it's usually a ribbon cable with an insulation-displacement connector, or IDC. Here's one with a male DB-9 on one end:

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

When you designing your extension board you can (within eagle) use any sort of connector that has 2 rows of 25 pins with 0,1" (2.54 mm) spacing. Check your design so that the holes of the connector are labeled exactly how the SXB board extension bus is labeled (viewed from top). When you later get the board from your pcb supplier you use a proper connector (look for "929852-01-25" @ Mouser) soldered on the bottom side of the pcb.

Precision socket strips for IC's are not suited. They are designed for thinner pins.

And yes - the number of connector types is somewhere between gooogle and infinity



edit (1) : see also http://forum.6502.org/viewtopic.php?f=1&t=3552&p=42745&hilit=65c265#p42792