Rob Cawsey

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10 years, 7 months ago.

LPC1768 How To Configure RTC To Use Internal Clock Source

Hi,

Title says it all, I'm struggling to figure out how to configure an LPC1768/mbed to use the the internal clock source for the RTC module. If anyone has any info or examples it would be helpfull.

Thanks.

1 Answer

Erik -
10 years, 7 months ago.

Looks like the RTC is only intended to be used with an external 32kHz crystal. Of course you can try using a PWM/timer output to generate that from the main clock, but a 32kHz crystal is the better solution.

External oscillator it is thanks, would i need to configure any registers to use the RTC?

posted by Rob Cawsey 26 Aug 2013

You can use standard C time functions, those will automatically configure the RTC, see: http://mbed.org/handbook/Time?action=view&revision=11592 (out of date revision, you can also check latest one, but personally I prefer the older one).

And if you require interrupts you can use: http://mbed.org/users/Sissors/code/RTC/

posted by Erik - 26 Aug 2013