RV5C387A_03 Datasheet, PDF (47/49 Pages) RICOH electronics devices division – I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC WITH VOLTAGE MONITORING FUNCTION

RV5C387A
8.3 Reading Time and Calendar Data
8.3-1 Ordinary Process of Reading Time and Calendar Data
Start condition
*¹
Read from clock and
calendar counters
*1) When reading from clock and calendar counters, do not insert stop
condition until all times from second to year have been read to prevent
error in reading time. (Detailed in “1.2-6 Data transmission under special
condition”.
*2) Take care so that process from start condition to stop condition will be
complete within 0.5sec. (Detailed in “1.2-6 Data transmission under
special condition”.
Stop condition
*²
8.3-2 Basic Process of Reading Time and Calendar Data Synchronized with Periodic Interrupt
Set Periodic Interrupt
Cycle Selection Bits
*¹
*1) This step is intended to select the level mode as a waveform mode for the
periodic interrupt function.
*^{2) This step must be completed within 0.5 second.}
*^{3) This step is intended to set the CTFG bit to 0 in the Control Register 2 to}
cancel an interrupt to the CPU.
Generate Interrupt in CPU
CTFG=1?
NO
YES
Read from Time Counter
Other Interrupt
and Calendar Counter *² Processes
Write “×,1,×,1,×,0,1,1”
to Control Register 2
*³
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