Bugzilla – Bug 16497
Super cap backup of real time clock unreliable
Last modified: 2010-11-19 09:06:08 UTC
FW 9023 with MSP 1333 Prelimanary test of the RTC on 4 units 3 out of 4 failed after 3.5 hours
Created attachment 6976 [details] Graph of average power outage duration in United States, 1990-2004 How long should Radio retain the time without power? It depends on how long the power is out. The attached graph shows the average duration of a power outage in the United States between 1990 and 2004. AFAICT, the graph shows that 24 hours handles 32 points on the graph, and doesn't handle 19 of the points. That means that 24 hours would handle is 63% of the points. To handle an additional 6 points, it needs to be 48 hours. That would be 75% of all points. To handle all points, it should retain time for 175 hours.
Tested in v9214, RTC stored the time correctly for slightly over 24 hours. I didn't test until failure, I was just verifying that it held for 24 hours. What's the spec?