Well I don't know what happened to my last response (eaten by the bit bucket I guess), but I was trying to say that it *might* be possible to do ISP anyway, as long as the two ends don't talk at the same time and as long as hearing their own responses back doesn't offend them (or maybe you can isolate them while they talk?).

But my main point in my now eaten post, was that ICP doesn't use any internal resources -- it runs out of it's own ROM. You just have to make the pins available.

GB