Well, thanks for your posts guys.

Erik, I'm just looking for smaller chips than p89c66x. I'm finding the Philips micro very good and I will continue with this 'black devils' as Per has already called them. The only issue is that the price is a little high for some kind of applications.

The AT89c2051 seems to be a way to build a low cost application (about 3 euros here against 12 for the p89c668). I think it should be interresting to have two hardware boards for new designs : one with p89c66x and one with a smaller micro for smaller applications.

In the past, I've used the Zilog Z86 familly with embedded OTP EPROM. One of the interest was that one of the chips was about 1 euro (about 1 dollar) in small quantites, allowing to replace many analog circuits and allowing to do some jobs difficult to do in analog. So, it could be easily included in some projects without increasing too much the application's cost. Note that the Zilog programmer/emulator costs only about 100 euros.

John, I understand your method for AT debugging. I've seen some programmers to build at very low cost so it could be a way to design without too high cost.

I will have a look to the tools Per was speaking about...

Regards
Stephane