M16C65 Datasheet, PDF (453/829 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M16C/60

Under development
M16C/65 Group
Preliminary Specification
This is a preliminary specification and is subject to change.
20. Real-Time Clock
20.3 Operations
20.3.1 Basic Operation
Real-time clock generates one-second signal from the count source selected in the RTCCSR register
and counts seconds, minutes, hours, a.m./p.m., a day, and a week.
Time and day to start counting are settable by registers RTCSEC, RTCMIN, RTCHR, RTCWK, and the
RTCPM bit in the RTCCR1 register. Current time and day are read from registers RTCSEC, RTCMIN,
RTCHR, RTCWK, and the RTCPM bit in the RTCCR1 register. However, do not read these registers
when the BSY bit in the RTCSEC register is 1 (while data is updated).
An interrupt request can be generated every second, minute, hour, day, or week. While bits RTCCMP1
to RTCCMP0 are 00b (no compare mode), use the RTCCR2 register to enable one of the periodic
interrupts triggered every second, minute, hour, day and week. When a periodic interrupt is generated,
the IR bit in the RTCTIC register becomes 1 (interrupt request).
Figure 20.3 shows Real-Time Clock Basic Operating Example, Figure 20.4 shows Time and Day
Change Procedure (No Compare Mode or Compare 1 Mode), and Figure 20.5 shows Time and Day
Change Procedure (Compare 2 Mode or Compare 3 Mode).
BSY bit
Approx.
62.5ms
1s
Approx.
62.5ms
Bits SC12 to SC00
in RTCSEC register
58
Undefined
59
Undefined
00
Bits MN12 to MN00
in RTCMIN register
03
Undefined
04
Bits HR11 to HR00
in RTCHR register
(Not changed)
RTCPM Bit
in RTCCR1 register
(Not changed)
Bits WK2 to WK0
in RTCWK register
IR bit in RTCTIC register
(when SEIE bit in RTCCR2 register
is 1 (enable periodic interrupt
triggered every second))
IR bit in RTCTIC register
(when MNIE bit in RTCCR2 register
is 1 (enable periodic interrupt
triggered every minute))
(Not changed)
This bit becomes low when an interrupt
request is accepted, or by setting the bit to 0.
BSY : Bit in RTCSEC register
Figure 20.3 Real-Time Clock Basic Operating Example
REJ09B0484-0030 Rev.0.30 Sep 09, 2008
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