In message 20050525083355.6524.qmail@web15904.mail.cnb.yahoo.com you wrote:
Thanks. Actually, it involves the grey area which a probelm was supposed to produce by hardware or software. The golden role is to check SW first.
You must be one of these hardware guys who always blame the software. I hope you have your asbestos ready in case you need them soon ;-)
I have been thinking one puzzle related u-boot itself. I noticed that sometimes u-boot would hang after relocation on my board. The chance is slim but have an effect on normal operation. Maybe 1 out of 10 times. Especially when power down and on in a short interval like no more than 1 minute. I don't know whether this symptom is due to SDRAM init problem.
This is one of the possible reasons.
Does anyone encounter such a problem? Ideas?
We've seen lots of "funny" problems with the many boards we lay hands on. Three more things to check:
* Check the voltages on your system: tolerances ok? spikes or other noise on the lines? especially close to the CPU? * Check the clocks. Check the clocks again. * check for unconnected pins, missing pull-ups or -downs, or incorrect resistor values
Best regards,
Wolfgang Denk