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FUJITSU MB91460 SERIES FR60 User Manual

Page 978

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Chapter 49 Real-Time Clock

8.Caution

lower than that of the peripheral clock (CLKP). If not, correct values cannot be read from WTHR/WTMR/
WTSR.

• Note that only byte-access is allowed to these register. So, when these registers are read at the very timing

of changing over the hour or minute boundary as shown below, there is a possibility of misjudging the time.
So, read several times to get a logically consistent value.

Example: Read begins at the second register: 02:59:59=> 03:59:59 => 03:00:00

Read begins at the hour register: 02:59:59 => 02:00:00 => 03:00:00

In this case, the current time should be interpreted as 3 o'clock.