Lpc2000

First of all a happy and successful New Year to everybody!

There have been some questions about 5V tolerance of analog pins.
All device on the market before the LPC2130 series can not tolerate 5V
on any pin that is configured or can be configured as analog input pin.
Starting with the LPC2130 series, pins that are not configured as
analog inputs (but could be) will no longer have a negative effect on
the ADC result. 
Please keep in mind that the pin 0.25 DAC output is not 5V tolerant
even  if used as digital I/O.  The effect will be that it starts
sinking current if not externally limited to the bitter end of thermal
destruction. So at the very least limit the current if you expect more
than Vdd on that pin.

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. 

Hope I did not add to the confusion but answered to some of your concerns.

Off to a good start, Robert