Lpc2000

Hi,

a follow up to my own message. I got additional information on the
3.3V / 5V tolerance issue. 
The e-mail that I got lets me quantify the time with 5V being present
while Vdd3 not being present at all (0V). Assuming the difference of
the two voltages is actually 5V, the expected lifetime of that
particular pin is several days. Let's assume a very slow regulator
following the 5V with 10 ms delay, this would result in > 1Mio power
on cycles for just 1 day of that expected lifetime. 
In a nutshell, this is nothing to worry about. 

Robert

> Another question was there about 3.3V being up and running while 5V
> are connected to some I/O pins. If you generate the 3.3V off the 5V
> input using a voltage regulator, the delay will be short to have 3.3V
> after 5V, in fact it might actually be at 3.3V before the voltage
> reaches 5V externally. The important issue is that during a longer
> period of time with a pin externally driven up to 5V and no Vdd for
> the microcontroller, there will be stress to the gate oxide and sooner
> or later the device will die. So, don't do that but do not worry about
> a 3.3V voltage generated from a 5V during power up. 
>