rtc chip
Dear IanP
I use PIC18F242 to control the RTC chip. Note that RTC chip is backuped with a
3V lithium cell.
I program the time into the RTC via MPU. After this I disconnect the I2C bus.
In this status I cut off the power and give it back again some times. Now I connect again the I2C bus and supply the board. The RTC may have lost it's time
for 10 or 20 minutes. The deiffernece of time is not always the same and it is not
sure that the RTC will loose it's time. I have used the PCF8583 RTC from the sampe company and never had such a problem. both IC's work with I2C bus.
The situation is a bit wear because it does not happen all the time.
I suppose that a a strange behaviour of the RTC chip due to power spikes could lead to this phaianomenon..........., I dont' know.
My regards