NXP Semiconductors PCA8565, PCF85x3 Contact information, NXP Semiconductors, Revision history

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NXP Semiconductors

UM10301

Revision history

Rev Date

01 20081223

User Manual PCF85x3, PCA8565 and PCF2123, PCA2125

Description

Initial version.

This application note / user manual is a complete update of a previous publication titled: “Application note for the Philips Real Time Clocks PCF8563,73,83,93” which did not have an official AN/UM number and is superseded by this document.

The contents were revised with lots of additional information added and errors in the examples corrected. Additionally it includes information with respect to recently introduced RTCs.

Contact information

For additional information, please visit: http://www.nxp.com

For sales office addresses, please send an email to: salesaddresses@nxp.com

UM10301_1		© NXP B.V. 2008. All rights reserved.
User manual	Rev. 01 — 23 December 2008	2 of 52

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Contents Abstract Info Content KeywordsDocument information Revision history Contact informationNXP Semiconductors Rev Date DescriptionIntroduction Features Register overview PCF8563 Address Register name BitEvent counter mode ComparisonFeatures Comparison of six real time clocksVoltage-low detector Power-on reset PORPower-on reset Oscillator-stop detection OscillatorVoltage-low detection Pierce Oscillator equivalent diagram Overview of internal and external oscillator capacitorsOscillator frequency determining components UM10301 + C Typical values for crystal and surrounding capacitors Parameter Value Unit SourceUsing an external oscillator Oscillation allowanceCrystal and crystal selection Effect of temperature Modes which don’t work− f nom Capacitors and capacitor selection Accuracy Influences on time accuracy Oscillator tuning Oscillator tuning 10.1 PCF2123 Offset register Year and leap year tracking Century and leap year, Daylight Saving TimeCentury tracking Daylight Saving Time DSTBlock Diagram PCF8563 Initialization and setting of alarm and timerInitialization of the RTC and setting the time Binary BCD AlarmSetting the alarm Register Comments AddressAlarm function Register Setting the timerSetting the timer Backup power supply Lithium Primary cellsBackup circuit using primary lithium cell Backup circuit using secondary cell NiCd or NiMH NiCd and NiMH secondary batteries13.3 Capacitors Charging the backup capacitor 1N4148 Diode selectionSome suggestions for diode D1 BAS716 BAS116 BAV170PCB layout guidelines PCB layout proposal for PCF8563 using leaded components Partial circuit switch down Hints to keep power consumption low Protection diodes0007 8473 ⋅ C b Rpmax as a function of bus capacitanceApplication diagram 1, I2C-bus interface Application diagram 2, SPI interfaceTimer Source clock frequency Delay for n = First period inaccuracy when using the timerTimer delays General countdown timer behaviourFirst period delay for timer counter value n Timer source clock Minimum timer period Maximum timer periodTiming requirements for I2C read and write Block diagram I2C interface and Time counters I2C interfaceSequence of events example Read Troubleshooting Oscillator startup time Checking for oscillationNo communication via I2C-bus References Wrong time and date, wrong clock speedDisclaimers Legal informationDefinitions TrademarksContents