M16C65 Datasheet, PDF (438/829 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. Real-Time Clock
20.1 Introduction
The real-time clock generates a 1-second signal from a count source and counts seconds, minutes,
hours, a.m./p.m., a day, and a week. It also detects matches with specified seconds, minutes, and hours.
Table 20.1 lists Real-Time Clock Specifications, Figure 20.1 shows a Real-Time Clock Block Diagram,
and Table 20.2 lists the I/O Port.
Table 20.1 Real-Time Clock Specifications
Item
Specification
Count source
f1, fC
Count operation
• Increment
• Compare mode 1 or not using compare mode
The count value is continuously used, and the count continues
• Compare mode 2
When a compare match is detected, the count value is set to 0
and the count continues.
• Compare mode 3
When a compare match is detected, the count value is set to 0
and the count stops.
Count start condition
1 (count starts) is written to the TSTART bit in RTCCR1 register
Count stop condition
0 (count stops) is written to the TSTART bit in RTCCR1 register
Interrupt request generation timing Select one of the following:
• Update second data
• Update minute data
• Update hour data
• Update day data
• When day data is set to 000b
• When the count data and the compare data match
RTCOUT pin function
Programmable I/O ports or compare output
Read from timer
When the RTCSEC, RTCMIN, RTCHR, or RTCWK register is read,
the count value can be read. The values read from registers
RTCSEC, RTCMIN, and RTCHR are represented by the BCD
code.
Write to timer
When bits TSTART and TCSTF in the RTCCR1 register are 0
(timer stopped), the RTCSEC, RTCMIN, RTCHR, and RTCWK
registers can be written to. The values written to registers
RTCSEC, RTCMIN, and RTCHR are represented by the BCD
codes.
Select function
• 12-hour mode / 24-hour mode switch function
• Compare output
Note:
1. In this manual, day refers to one day of the week. Refer to 20.2.4 “Real-Time Clock Day Data
Register (RTCWK)” for details.
REJ09B0484-0030 Rev.0.30 Sep 09, 2008
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