Datasheet

78K0/Kx2-L CHAPTER 10 REAL-TIME COUNTER
R01UH0028EJ0400 Rev.4.00 374
Sep 27, 2010
Figure 10-3. Format of Real-Time Counter Control Register 0 (RTCC0)
Address: FF9DH 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
Note 1
RTC1HZ pin output control
0 Disables output of RTC1HZ pin (1 Hz).
1 Enables output of RTC1HZ pin (1 Hz).
RCLOE0
Notes 1, 2
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
Rewrite the AMPM value after setting RWAIT (bit 0 of RTCC1) to 1. If the AMPM value is changed, the values of
the hour count register (HOUR) change according to the specified time system.
Table 10-2 shows the displayed time digits.
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)
When changing the values of CT2 to CT0 while the counter operates (RTCE = 1), rewrite the values of CT2 to CT0
after disabling interrupt servicing INTRTC by using the interrupt mask flag register. Furthermore, after rewriting the
values of CT2 to CT0, enable interrupt servicing after clearing the RIFG and RTCIF flags.
Notes 1. 78K0/KC2-L (44-pin and 48-pin products) only
2. RCLOE0 and RCLOE2 must not be enabled at the same time.
Caution If RCLOE0 and RCLOE1 are changed when RTCE = 1, a glitch may be generated on the 32.768
kHz and 1 Hz output signals.
Remark ×: don’t care