Lpc2000

I'm new to this group and to the 2000 architecture.  I have a design that 
was initially coded on the IAR 2106 dev board.  We've now moved that to our 
own hardware.

The problem that I'm experiencing is that I cannot flash the controller on 
my hardware more than once.  Once flashed, the controller is unresponsive 
to attempts to connect to the loader.  The design is a mixed 3v/5v 
design.  I discovered that I was driving the controller's reset pin with a 
5v signal (banging my forehead on the desk).  So, we hacked the board and 
are now driving reset with a 3v signal.  I had thought that that would 
solve my problem - 5v eventually burns out the reset pin circuit so of 
course I can't communicate with the loader because I can't reset the 
controller.  Application code runs fine.

While the 5v on a 3v pin surely must have contributed, it doesn't seem to 
be the entire cause.  We fixed the 5v reset problem but still can only 
program virgin controllers.  Since, P0.14 is a port pin I didn't change the 
circuit that drives it.  Now I've gotten to wondering if that pin and the 
perhaps the Rx/Tx connections to serial 0 must also be at 3v levels during 
programming.  The data sheet appears somewhat vague about just which pins 
are 5v tolerant but it does say that there are 32 general purpose I/O pins 
that are and interestingly enough, P0 just happens to be 32 bits wide, 
therefore I can assume, can I not, that those are the pins that are 5v 
tolerant?

If any of you have had this or similar problems with flashing the 210x 
family, I surely appreciate whatever help you can send my way.

There isn't any "security" bit somewhere that would prevent me from 
connecting to the loader is there?  That makes no sense to be but there 
have been stranger things ...


Scott

Systronix, Inc
Salt lake City, Utah