Searching back a bit I see that quite a few people have had problems
with the ISP code from Philips.
Today I tried to get this going but it just would not work, so I
thought I'd debug it a bit.
There seem to be two problems:
1) Some computers (eg. my laptop, and I believe some desktops with
power saving features) might be sending out something thatlooks like
break when the port is not active. This, I hunch, can confuse the ISP
firmware's autobaud detection.
2) The ISP code sends out one '?', that's it! If there was a retry
then perhaps it would get synchonised more reliably. I have
encountered situations where up to 75 or so '?' retries were required
before I got synchronisation.
I think these two issues are most likely to occur in boards using a
manual reset mechanism. Boards using the DTR/RTS triggered reset
be getting a more reliable boot-up.
Anyway Philips, it would be nice if you could fix these problems...