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To read system time, read register 0057h first.
This reads the current system time to a cache and prevents the value from changing when other system time registers are accessed.
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After reading the register 0057h, read registers 0058h ... 005Ch to get month, day of
month, hours, minutes, and seconds.
The reading order of these registers is free.
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To write the system time, set the year, month, day of month, hours, and minutes by the
means of the registers 0057h ... 005Bh.
This writes the date to the cache.
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To finish updating the system time, write seconds to register 005Ch.
This updates the system time immediately by applying all the recent values from the cache.