Re: [Paparazzi-devel] YAPA2 help needed

[Chris]

I think i am on to something.
I remembered that the board worked fine for a day or so when it was 
powered directly from 4S lipo.
Now the only difference is the added 25.2v to 12v psu AND that when i 
was using 4S the receiver was powered from the onboard 5v regulator (i 
connected a wire to the 5v psu) not from the BEC as it is supposed to be 
in YAPA2.
Could it be that the PPM signal from the receiver is applied before the 
LPC gets power ie  having a situation where a pin has an input of 5v 
before the LPC has it's 3.3v and this damages the LPC2148?

From the LPC2148 errata:
On port pin P0.25 (when configured as general purpose input pin), 
leakage current
increases when the input voltage is Vi > Vdd I/O + 0.5 v. Care must be 
taken to limit the
current to less than 4 mA by using a series limiting resistor.

Strangely P0.25 is the IRH2 analog input which i use for voltage sensing 
but this input has a 10Kohm
resistor so a current of 4ma is not possible but i don't know about the 
PPM input.
Maybe this applies to other inputs also.
Is this possible (Anyway it is the only thing i can think of so any help 
or opinion is welcomed)?
Also i noticed that the LPC might not work anymore but it is not 
completely dead, it produces unusually high amount of heat.
Chris