Datasheet

CHAPTER 9 REAL-TIME COUNTER
User’s Manual U18698EJ1V0UD
265
Figure 9-3. Format of Real-Time Counter Control Register 0 (RTCC0)
Address: FF89H After reset: 00H R/W
Symbol <7> 6 <5> <4> 3 2 1 0
RTCC0 RTCE 0 RCLOE1 RCLOE0 AMPM CT2 CT1 CT0
RTCE Real-time counter operation control
0 Stops counter operation.
1 Starts counter operation.
RCLOE1 RTC1HZ pin output control
0 Disables output of RTC1HZ pin (1 Hz).
1 Enables output of RTC1HZ pin (1 Hz).
RCLOE0
Note
RTCCL pin output control
0 Disables output of RTCCL pin (32.768 kHz).
1 Enables output of RTCCL pin (32.768 kHz).
AMPM Selection of 12-/24-hour system
0 12-hour system (a.m. and p.m. are displayed.)
1 24-hour system
• To change the value of AMPM, set RWAIT (bit 0 of RTCC1) to 1, and re-set the hour count register (HOUR).
• Table 9-2 shows the displayed time digits that are displayed.
CT2 CT1 CT0 Constant-period interrupt (INTRTC) selection
0 0 0 Does not use constant-period interrupt function.
0 0 1 Once per 0.5 s (synchronized with second count up)
0 1 0 Once per 1 s (same time as second count up)
0 1 1 Once per 1 m (second 00 of every minute)
1 0 0 Once per 1 hour (minute 00 and second 00 of every hour)
1 0 1 Once per 1 day (hour 00, minute 00, and second 00 of every day)
1 1
×
Once per 1 month (Day 1, hour 00 a.m., minute 00, and second 00 of
every month)
After changing the values of CT2 to CT0, clear the interrupt request flag.
Note RCLOE0 and RCLOE2 must not be enabled at the same time.
Caution If RCLOE0 and RCLOE1 are changed when RTCE = 1, a pulse with a narrow width may be
generated on the 32.768 kHz and 1 Hz output signals.
Remark ×: don’t care