Hi All,

I am not sure how many people here are using NXP (founded by Philips) LPC900's Microcontrollers.

I did a little spice simulation of the ISP to ICP bridge circuit in application note AN10258_2.pdf.... (MCB900 Bridge circuit).

According to my LTSpice simulation of the circuit the NPN transistor does not deliver enough Vdd voltage to the target Micro for programming..... and I have built the circuit and confirmed the problem exists in real hardware as well.

My findings are on the Flash Magic Web site.
http://forum.flashmagictool.com/index.php...26#msg3326
The 2nd POST MS Word Doc has my findings...

QUESTIONS
Q1
Is my model of the Quasi-Bidirection output OK? Is 50k typical for the pull-up?

Q2
Are there any comments on my proposed circuit.

Thanks in advance

Joe