Hello,
I was hoping to hear your opinion about a serious problem I have - it is either I solve it or reduce my LPC2478 CPU speed from 72[MHz] to 64[MHz] (11% loss. The problem does not seem to be occurring at lower MHz settings). I posted about this in the past but it was a long time ago. When I place a controller in an environmental chamber and increase the temperature to 80+ Celsius degrees, I often see data abort exceptions, and sometimes I get the impression that the PC takes a hike (even the firmware LED that blinks every 1 second becomes irregular for a while before it stops). The program is launched by a boot loader and has a lower level supporting firmware layer that handles some interrupts (not all). I also see that if RTX is not started at all (but the application hangs in a "for (;;)" loop instead, hence the bootloader and firmware layer were/are involved, but the application is idle) - the system never crashes! I have excluded, as far as I could tell, the roll of external memory or RTX in this situation. However, I still suspect RTX a little (even though my test programs never crashed). My question: did you ever encounter such a situation? Where do I look best? can this be the result of a misbehaving peripheral? NXP have confirmed the LPC2478 is not the reason.
Maybe it is a solder problem.
I doubt it. it occurs on many systems, and the hardware has been verified.
"if I learn something new, I will post it."
Like when something is not related to Keil tools.
Egads.
I understand that you have serious problems in finding something that invokes your intellect. do yourself (and us all, unless you have something meaningful to say) a favor, then: be gone.
If you think that the DRAM is the problem, I would try:
- To do a small app where: write to the whole memory (at the highest bandwidth) and then verify. Make an infinite loop waiting for a fail or exception. - Write down info like time-temp. - Run the app for DRAM and then for IRAM or if you have many boards do it at the same time with 3-4 of them.
Try increasing the temperature to see if the problem gets any worse.
Leandro,
Despite "stunned Steve"'s doubt about me, I have already tried this (but thanks for the tip anyway) - all my test programs, including the one you described work well under the above conditions and worse. still searching for the smoking gun/component!
Despite "stunned Steve"'s doubt about me
Should of course read:
Despite "stunned Steve"'s doubts about me
I guess you (unlike me, unfortunately...) have found your smoking gun. _SNIFF_ !
Have you checked for dry joints?
Nevill,
Yes, but not me personally. It seems that until 80 degrees (and perhaps slightly more) everything is fine, but them there is a rapid failure as the temperature increases. can it be that the coating in the print disturbs heat dissipation?
What is the humidity of your test chamber?
humidity: 0%.
can it be that the coating in the print disturbs heat dissipation?<p>
Hm, the whole print is coated (including the components)?
yes.
"humidity: 0%."
Whew, dry heat man. Doesn't sound likely to use.
Are you absolutely sure about that?