OM11059,598

lines which may pick up noise. Avoid any tracks with high frequency signals (fast edges)

close to the RTC, quartz, or quartz interconnect.

The interface uses a three-line standard SPI protocol: chip enable, serial clock, serial

data I/O operating up to 8 MHz.

Supply voltage: The RTC is specified from 1.8 V to 5.5 V. The RTC, excluding the SPI-

bus interface, is however operating down to a lower voltage. It is recommended to have a

decoupling capacitor on the VDD-VSS rails close by.

Due to the low power consumption of below 1 μW, no precautions for heat dissipations

are required.

CLKOUT can be used to measure the frequency or be used as reference for frequency

The OM11059 allows to easily demonstrate operation of the PCF85063BTL with SPI-bus

interface. No need to solder the tiny package to a breadboard 100 mil connector for

straight forward connections.

Straight forward interfacing:

- Connect supply voltage (e.g. 3.3 V): VSS to pin 1, VDD to pin 2

- Connect SPI-bus: CE to pin 4, SCL to pin 3, SDI/O to pin 7

- Communicate to the RTC

protocol applies.

Theoretically there is no lower speed limit, however a read or write access to the RTC

must be finalized within one second after initiating it, otherwise time counter increments

could be lost. During access, the time registers of the RTC are frozen and after the read

or write sequence is completed, a seconds increment is executed if required.

The clock tracks the actual time from seconds to year. It must be initially set to the

correct time of the actual time zone. The days per month and leap year are corrected

automatically. Leap years are assumed whenever the year is dividable by 4.

The RTC can be programmed to generate an interrupt every 30 seconds or every

60 seconds.