Hello all,

I would like to know if there's an hardware application note describing how to back up and recover the AT91RM9200's RTC in case of a sudden shut-down ?

How is the RTC supported under Linux ?

Is it better to use an external RTC ?

Thank you for your answers..

Jean Lee

Hi Jean,

I can not answer your Linux question.

If the power loss is greater than about 10 seconds, then an external RTC will work better. The reason is that the VDDCORE (1.8 V) will continue to draw 31.7 milliamps.

An external RTC from Maxim/Dallas has current draw typical of 400 nanoamps when power is lost. A battery or supercap can save hold the voltage on these ICs for a much longer time.

Regards,
Mark