Thank you for your prompt advice.
Even if I use rtc.setDate() and rtc.setTime() to set the date and time, they will inevitably be out of sync with the PC time.
I want to synchronize the RTC with the PC clock.
On DS-3232, rtc.ajust() seems to be an easy way to synchronize with PC clock, but it does not seem to work on PCF8563.
Please advise me if there is a better way.