user manual

Rev. 5.00, 09/03, page 407 of 760
Section 13 Realtime Clock (RTC)
13.1 Overview
The SH7709S has a realtime clock (RTC) with its own 32.768-kHz crystal oscillator.
13.1.1 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