8.3 Reading Time and Calendar Data
8.3-1 Ordinary Process of Reading Time and Calendar Data
Read from clock and
8.3-2 Basic Process of Reading Time and Calendar Data Synchronized with Periodic Interrupt
Generate Interrupt in CPU
to Control Register 2
Set Periodic Interrupt
Cycle Selection Bits
Read from Time Counter
and Calendar Counter
*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
*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
*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.