RTC clock does not keep time during main power loss

[ToPe_1312931]

We are providing 1.8V on pin VBACKUP during main power loss and have a 32.768 kHz crystal on pins P0.0 and P0.1 of a CY8C6247BZI-D54. We have used the example RTC code, set the time and then removed main power. Verified VBACKUP is still present and the crystal is oscillating. Left alone for about an hour. Restored main power and read the RTC over UART. It jumped back about a day.

Any explanations for this?

Another question is, could we provide the clock using a digital oscillator instead of a crystal?

Thank you in advance for any help.

[BragadeeshV · Accepted solution]

Hi ToPe_1312931​,

Please go through the discussions in the following threads which might help resolve your issue:

More Real-Time Clock woes

Battery/Super Capacitor backup power / RTC

Regards,

Bragadeesh

[VenkataD_41]

Hi

Another question is, could we provide the clock using a digital oscillator instead of a crystal?

For this question, the answer is YES. please find the following image from the clock configurator.

For RTC based query, please check the code example from the links below and let us know if the issue reproduces in code examples also.

https://www.cypress.com/documentation/code-examples/ce218964-psoc-6-mcu-rtc-daily-alarm

https://www.cypress.com/documentation/code-examples/ce216825-psoc-6-real-time-clock-basics

Thanks

Ganesh