SH7708 datasheet(337/633 Pages) RENESAS

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Section 12 Realtime Clock (RTC)

12.1

Overview

The SH7708 Series has a realtime clock (RTC) with its own 32.768-kHz crystal oscillator.

12.1.1

Features

• Clock and calendar functions (BCD display): seconds, minutes, hours, date, day of the week,

month, and year

• 1-Hz to 64-Hz timer (binary display)

• Start/stop function

• 30-second adjust function

• Alarm interrupt: frame comparison of seconds, minutes, hours, date, day of the week, and

month can be used as conditions for the alarm interrupt

• Cyclic interrupts: the interrupt cycle may be 1/256 second, 1/64 second, 1/16 second, 1/4

second, 1/2 second, 1 second, or 2 seconds

• Carry interrupt: a carry interrupt indicates when a carry occurs during a counter read

• Automatic leap year correction

12.1.2

Block Diagram

The following abbreviations are used in the block diagram of the RTC (figure 12.1):

R64CNT: 64-Hz counter

RSECAR: Second alarm register

RSECCNT: Second counter

RMINAR: Minute alarm register

RMINCNT: Minute counter

RHRAR: Hour alarm register

RHRCNT: Hour counter

RWKAR: Day of the week alarm register

RWKCNT: Day of the week counter

RDAYAR: Date alarm register

RDAYCNT: Date counter

RMONAR: Month alarm register

RMONCNT: Month counter

RCR1: RTC control register 1

RYRCNT: Year counter

RCR2: RTC control register 2

SH7708 Datenblatt(PDF) 337 Page - Renesas Technology Corp