Lpc2000

From: "dsidlauskas1"
> I got tired of waiting for Philips so I wrote my own simple program to
> investigate this stack problem. I used Keil.  The code below first
> fills the stack area so that the contents of the stack is equal to the
> stack address. This makes it easier to see what's being popped.
>
> With a break at the POP {R4}, SP=0x40000180, PC=0x0180. When the POP
> is executed R4 ends up with the correct value of 0x40000180, so I
> don't experience the problem. I've tried this both with MAM on and off.
>
> Could this be a JTAG debug problem?

Hmmm...
I've seen two bugs in my 30 years of computerbuilding that looked like this.
Both were semi-analog problems: specific patterns on the data- and
addressbus causing analog crosstalk between lines, which then didn't meet
the timing requirements.

Could someone that can reproduce the bug try some things:

1. Try the program at a much (2x) lower speed (reprogram the PLL)

2. Check for proper decoupling of this chip (100nF ceramic SMD on EACH
Vss/Vdd pin combination, within 5mm from the chip). If not properly
decoupled, add these and try again.

3. Try at a lower temperature (freeze the board and start it quickly, or put
a bag of ice on top).

I've no board yet for the LPC2138 sample I just received, or I'd try it
myself (removing proper decoupling, that is). This is a nice bugyy to catch!

Regards,
Arie de Muynck