DS2415

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READ CLOCK [66h]

The Read Clock command is used to read the device control byte and the contents of the real time clock

counter. After having received the most significant bit of the command code the device copies the actual

contents of the real time clock counter to the read/write buffer. Now the bus master reads data beginning

with the device control byte followed by the least significant byte through the most significant byte of the

real time clock. After this the bus master may continue reading from the DS2415. The data received will

be the same as in the first pass through the command flow. The Read Clock command can be ended at

any point by issuing a Reset Pulse.

WRITE CLOCK [99h]

The Write Clock command is used to set the real time clock counter and to write the device control byte.

After issuing the command, the bus master writes first the device control byte, which becomes

immediately effective. After this the bus master sends the least significant byte through the most

significant byte to be written to the real time clock counter. The new time data is copied from the

read/write buffer to the real time clock counter and becomes effective as the bus master generates a Reset

Pulse. If the oscillator is intentionally stopped the real time clock counter behaves as a 4-byte non-

volatile memory.