RV-8564 Datasheet, PDF (8/40 Pages) MICORO CRYSTAL SWITZERLAND – I2C-Bus Interface Real Time Clock

Micro Crystal
Real Time Clock / Calendar Module
RV-8564
6. FUNCTIONAL DESCRIPTION
The RV-8564 RTC module combines a RTC IC with on chip oscillator together with a 32.768 kHz quartz crystal in a
miniature ceramic package.
The RV-8564 contains sixteen 8-bit registers with an auto-incrementing address register, a frequency divider which
provides the source clock for the Real Time Clock (RTC), a programmable clock output, a timer, a voltage low
detector and a 400 kHz I²C bus interface.
All 16 registers are designed as addressable 8-bit parallel registers although not all bits are implemented. The first
two registers (memory address 00h and 01h) are used as control and/or status registers. The memory addresses
02h through 08h are used as counters for the clock function (seconds up to year counters). Address locations 09h
through 0Ch contain alarm registers which define the conditions for an alarm. Address 0Dh controls the CLKOUT
output frequency. 0Eh and 0Fh are the timer control and timer registers, respectively.
The seconds, minutes, hours, days, weekdays, months, years as well as the minute alarm, hour alarm, day alarm
and weekday alarm registers are all coded in BCD format.
When one of the RTC counters is read (memory locations 02h through 08h), the contents of all counters are frozen
at the beginning of a read cycle. Therefore, faulty reading of the clock / calendar during a carry condition is
prevented.
6.1. CLKOUT OUTPUT
A programmable square wave is available at the CLKOUT pin. Frequencies of 32.768 kHz, 1024 Hz, 32 Hz and 1
Hz can be generated for use as system clock, microcontroller clock or input to a charge pump. CLKOUT is a CMOS
push-pull output, and if disabled it becomes logic 0.
7. DEVICE PROTECTION DIAGRAM
CLKOE
V_DD
CLKOUT
INT
SCL
V_SS
SDA
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