LPC1788 RTC's General purpose registers

[lihai]

Dear All,

     I have a question about LPC1788 RTC's General purpose registers 0-4,   I write 1 to General purpose registers 0 , then power off(without battery powered) , General purpose registers 0 value changed to 0 after power on. 

     the user manual said : These registers can be used to store import information when the main power supply is off .  It seems that General purpose registers can not store information without main power supply & battery power supply?

[soledad]

Hi,

The RTC block includes 20 bytes of battery-powered backup registers, allowing system status to be stored when the rest of the chip is powered off. Battery power can be supplied from a standard 3 V Lithium button cell. 

I hope this clarifies.

Have a great day,
Sol

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