After not receiving a response from WDC concerning when the 65C51 would be available, I started looking for a replacement. I came across the Exar UART product line. Something that made it stand out immediately was the availability of a Motorola bus interface on some of the models.

I recently purchased a 16L580 from Future Electronics that has both Intel and Motorola bus interfaces.

This is a 32 pin QFN surface mount part that measures only 5mm square. I bought a Schmartboard adapter board and had it up and running on my SBC-3 core with only a little troubleshooting. I seem to be getting drawn into the whole surface-mount generation.

It has R/W, /CS, /IRQ, and /RES pins that connect right to the 65Cxx families. There is no PHI2 so the /CS needs to be gated with PHI2 externally. It is running well at 8 MHz and should be able to go even faster.

For those wanting a through-hole part, try the XR68C681. It comes in a 40 pin DIP package and has two UART's on board. Future Electronics has those in stock too.

Comments and questions welcome.

Daryl

I'm still really skeptical of surface mount components, personally. Particularly since a lot of the chips I am interested are increasingly only available in BGA packages. (e.g., SeaForth-24 chips are only 80 pins in size, but yet, at only a handful of millimeters on a side, you're looking at BGA packaging. ).

Can you describe in somewhat greater detail your experiences working with surface mount components so far?

Sure. I'll start a new topic for that discussion.

The info is now here:
viewtopic.php?t=1228

Daryl

Yes, BGA's will require some sort of reflow soldering.

I have this link as a possible solution from the ExpressPCB website:
http://www.stencilsunlimited.com/produc ... 08bb7379a4

Daryl

Hah, at my production volumes (specifically *one*), $145, not including "additional fees," is a bit steep. No thanks.