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.
Per,
that's a good idea that I haven't tried yet. thanks!
this situation seems to be directly related to the external RAM being addressed by both the application and the LCD controller. if the refresh rate of the LCD controller is reduced, or another type of software is flashed on the controller that does not benefit from the LCD controller - the issue disappears. I will have to adjust the timing parameters of my external RAM, it seems.
For the amount of stuff (and content of the stuff) you're posting, you would be better off with twitter :o
I don't know about you, but for me, these problems are the cream of the crop of this kind of line of work. almost every problem is a mystery, every problem can be solved (?) in different ways. did I enjoy sitting 3 days in front of an environmental chamber (I have a few burn makes!) ? no way, and the problem is not solved yet (but the probable cause known). but in the end, it is/was a lot of fun!
I second this!!, thats a real engineer soul, we are in some way... masochist geeks :)
related to the external RAM being addressed by both the application and the LCD controller.
A conclusion you made impossible for anyone else to arrive at, by not mentioning anything about an LCD before, much less that it shared external RAM with the CPU. Is that dual-ported RAM, or how else do you organize shared access?
The data transfers LCDController <-> Memory are done by DMA, and there is an automatic mechanism for arbitration, This should not be a problem.
But it should be taked into account if the Video Buffer is located in DRAM and you want to test the DRAM PerÂ's suggestion.
"I second this!!, thats a real engineer soul, we are in some way... masochist geeks :)"
I would totally agree with that, I've been involved in plenty of projects where I've been totally engrossed for weeks/months on end, keeping a note pad by my bed for when I wake up with 'the ultimate answer' (much to the annoyance of my beloved wife).
But ... the difference is, most don't keep trying to share this random blabber out.
Have you ever been to a party and sat next to Mr. Boring?