Hello, here is the latest news about the investigation of bug #1024 (oscillating re-camping).
I finally received a GTA02 which exposes the behavior of bug #1024 and a second one is on the way (Thanks again to those who send me the phones, you know who you are). This one GTA02 which I am already playing with for some time shows re-camping in a very extreme form, if the phone goes into "Deep Sleep" while receiving the PCH, the next reception will fail immediately. It does not care how long this "Deep Sleep" period is, the next PCH reception will simply fail. My other GTA02 phones work perfectly in the same situation (a simulated test cell) and show no problems at all with "Deep Sleep". To find out if the 32 kHz oscillator is responsible for the problem, I connected an external, stable and accurate clock signal: No difference, still the extreme behavior in "Deep Sleep". Finally, after a while I found out that the problem goes away if I warm up the Calypso chip by a few degrees. The other chips of the GSM chipset (Digital Baseband and RF Transceiver) or the 32 kHz and 26 MHz oscillator don't care about warming, only if I warm up the Calypso, the problem goes away and this GTA02 behaves as good in "Deep Sleep" as my other GTA02 do. Additionally if the Calypso cools down again, it slowly begins to expose problems in "Deep Sleep" every now and then until finally the extreme behavior (PCH reception failure immediately after "Deep Sleep") is back again. Its still too early to conclude anything from this observation, its just one GTA02. I am waiting for the second GTA02 to find out if it behaves the same. I am also trying to find out if there is a way to remove this "Deep Sleep" problem with a modification of the GSM firmware. The transition into "Deep Sleep" and back again is a rather complex process, there are all three GSM chips involved, so there is a chance that things go wrong here at some point. However the big problem is (again and as usual) that we don't have the Source Code of this part of the firmware. So its rather time consuming to find and understand the responsible parts of firmware, patch them and test the result. So this is it for today, just to let you know that bug #1024 is not forgotten ;-) Best regards, Dieter _______________________________________________ hardware mailing list [email protected] http://lists.openmoko.org/mailman/listinfo/hardware
