Lpc2000

----- Original Message ----- 
From: "johnsonnenberg99" <johnsonnenberg99@...>
To: <lpc2000@yahoogroups.com>
Sent: Friday, February 03, 2006 7:03 PM
Subject: [lpc2000] Unrelialble 2132 start-up problem.


> My LPC2132 fails to start running about 1/100 power-ups. 99 out of
> 100, everything is OK.
> The Symptoms when if fails:
> a) Crystal does not oscillate. No voltage on either crystal osc
> pin.
> b) No firmware appears to ever run or initialize anythign in my
> hardware.
> c)I/O pins are still inputs.
> d)P0.14 is pulled low by CPU (I have a 10K P/U on it).  This
> symptom baffles me.
>
> When it is broke, I tried asserting reset low manually.  It does not
> clear the condition.   P0.14 stays stuck low, even with a manual
> reset. (power stays on through the reset. )
>
> I have checked the usual issues (P0.31 is pulled-up w/10K, P0.14 is
> pulled up w/10K, P1.20 is pulled up w/4.7K, PU on all JTAG lines
> except 10K PD on TCK)
>
> I've got a number of boaords doing this.  Power on, reset was
> assered properly, but XTAL does not start.  CPU appears to be
> dead.    Any ideas would be much appreciated.
>
> Some I/O pins go to circuits that have zigh-z (>1Mohm) paths to 5V,
> and the 5V does come up before the 3.3.  Could this be it?
>
> Thanks in advance for any comments.

The 5 V on the I/Os before power is applied could be the cause. I don't know 
about the '2132, but it is mentioned in the '2106 data - there shouldn't be 
any voltage on the pins before the Vdd3 supply is present, if I am reading 
it correctly.

Leon