Micro Crystal
Ultra Small Real-Time Clock Module with SPI-Bus Interface
RV-8063-C7
October 2018
8/58
Rev. 1.1
FUNCTIONAL DESCRIPTION
2.3.
The RV-8063-C7 is a low power CMOS real-time clock/calendar module with embedded 32.768 kHz Crystal. The
CMOS IC contains 18 8-bit registers with an auto-incrementing register address, a frequency divider which
provides the source clock for the Real Time Clock (RTC), a programmable clock output, and SPI-bus with a
maximum data rate of 7 Mbit/s. An Offset register allows to digitally compensating the frequency deviation of the
32.768 kHz oscillator.
The built-in address register will increment automatically after each read or write of a data byte up to the register
11h. After register 11h, the auto-incrementing will wrap around to address 00h (see following Figure).
Handling address registers:
00h
01h
02h
03h
:
0Fh
10h
11h
Address
wrap around
auto-
increment
All registers (see REGISTER OVERVIEW) 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 status register.
The register at address 02h is an Offset register allowing the compensation of time deviation.
The register at address 03h is a free User RAM byte.
The addresses 04h through 0Ah are used as counters for the clock function (seconds up to year counters).
Address locations 0Bh through 0Fh contain alarm registers which define the conditions for an alarm.
The registers at 10h and 11h are for the timer function.
The Seconds, Minutes, Hours, Date, Month and Year as well as the corresponding alarm registers are all coded in
Binary Coded Decimal (BCD) format. When one of the RTC registers is written or read, the contents of all time
counters are frozen. Therefore, faulty writing or reading of the clock and calendar during a carry condition is
prevented for up to 1 second.
