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UM10301
User Manual for NXP Real Time Clocks PCF85x3, PCF85x63,
PCA8565, PCF2123, and PCA21125
Rev. 2.1 — 23 July 2015
Document information
Info
Content
PCF8563, PCF8583, PCF8593, PCA8565, PCF85263, PCF85363,
Keywords
PCF85063, PCF2123, PCA21125, PCF2120, RTC, real time clock,
timekeeping, crystal, 32.768 kHz, backup.
This user manual aims to assist a user of above mentioned Real Time
Abstract
Clocks in achieving successful design-in and application. It contains
useful hints with respect to electrical schematic and PCB layout as well
as code examples for the well-established NXP PCF8563 and related
Real Time Clocks. Also the more recent Real Time Clocks PCF2123 and
PCA21125 have been taken into account.
User manual
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Table of Contents
Related Manuals for NXP Semiconductors PC 85 3 Series
Summary of Contents for NXP Semiconductors PC 85 3 Series
- Page 1 UM10301 User Manual for NXP Real Time Clocks PCF85x3, PCF85x63, PCA8565, PCF2123, and PCA21125 Rev. 2.1 — 23 July 2015 User manual Document information Info Content PCF8563, PCF8583, PCF8593, PCA8565, PCF85263, PCF85363, Keywords PCF85063, PCF2123, PCA21125, PCF2120, RTC, real time clock, timekeeping, crystal, 32.768 kHz, backup.
- Page 2 RTCs. Contact information For more information, please visit: http://www.nxp.com UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 2 of 54...
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Page 3: Introduction
The application note is concluded with a short chapter on trouble shooting. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 4: Features
BCD format can easily be displayed in human-readable style without conversion. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... - Page 5 <weekday alarm 0 to 6> CLKOUT control timer control timer <timer countdown value> UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 5 of 54...
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Page 6: Comparison
UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 6 of 54... - Page 7 UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 7 of 54...
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Page 8: Fig 1. Power-On Reset
• The power has gone away and then come back again; • When the oscillator stops running. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 8 of 54... -
Page 9: Fig 2. Voltage-Low Detection
UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 10: Fig 4. Pierce Oscillator Equivalent Diagram
[1] Can be used with 9 pF and 12.5 pF as well if external capacitance is added UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 11: Fig 5. Oscillator Frequency Determining Components
The external components of the oscillator have to be chosen such that the UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 12: Fig 6. Graph Of Oscillator Frequency As Function Of Load Capacitance C L
C and C STRAY UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 12 of 54... - Page 13 Taking the numbers from Table 4 yields for L and Q: UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 13 of 54...
- Page 14 Murata TZB04 trim capacitor Vishay Beyschlag, datasheet ceramic multilayer capacitor, C0G UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 14 of 54...
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Page 15: Oscillation Allowance
This reduced signal can then be applied to the OSCI UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 16: Pcf2123
This initial error UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 17: Fig 7. The Deviation In Frequency Vs. Temperature Of A Typical 32.768 Khz Crystal
UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 17 of 54... - Page 18 125 °C. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015...
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Page 19: Capacitors And Capacitor Selection
For the decoupling of the RTC, use a capacitor with X7R dielectric. Using SMD UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 20: Accuracy
28 °C and quite stable. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 21: Fig 8. Influences On Time Accuracy
UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 21 of 54... -
Page 22: Oscillator Tuning
Remark: Touching the adjustment screw often causes the capacitance to shift. The setup is shown in Fig 9. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 22 of 54... -
Page 23: Fig 9. Oscillator Tuning
The signal is then fed as input to the tuning gear. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 23 of 54... -
Page 24: Pcf2123 Offset Register
For more details, refer to the PCF2123 datasheet. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 25: Century And Leap Year, Daylight Saving Time
DST are advised to design their products such that firmware handles DST changes. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 25 of 54... -
Page 26: Fig 10. Block Diagram Pcf8563
In this example the time to be set is Friday, July 16 2008, 2:45 pm. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 27: Alarm
1 0 1 0 0 0 1 0 C slave address, write UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 27 of 54... -
Page 28: Fig 11. Alarm Function
Fig 11. The interrupt has to be reset by software. Fig 11. Alarm function UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 28 of 54... -
Page 29: Setting The Timer
Refer to chapter 17 “First period inaccuracy when using the timer” for further details on timer operation. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 29 of 54... -
Page 30: Backup Power Supply
Non-rechargeable lithium batteries (primary cells) require two blocking components UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 30 of 54... -
Page 31: Fig 12. Backup Circuit Using Primary Lithium Cell
UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 31 of 54... -
Page 32: Fig 13. Backup Circuit Using Secondary Cell (Nicd Or Nimh)
Fig 13. Backup circuit using secondary cell (NiCd or NiMH) UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 32 of 54... -
Page 33: Capacitors
The application is very simple, refer to Fig 13. Here the supercap takes the place UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 34: Charging The Backup Capacitor
: The backup capacitor voltage when backup starts. Cbackupstart UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 34 of 54... -
Page 35: Diode Selection
5 nA Price indication, relative w.r.t. 3.5x 1N4148 (0.02 $) UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 35 of 54... -
Page 36: Pcb Layout Guidelines
GND exists and thus it is ensured that no unknown UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 37: Fig 14. Pcb Layout Proposal For Pcf8563 Using Leaded Components
UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 38: Fig 15. Pcb Layout Proposal For Pcf8563 Using Smd Components And Guard Ring
This allows for partial circuit switch down where the RTC still runs and the rest of the application is powered down. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 38 of 54... -
Page 39: Fig 16. Protection Diodes
See section 13.4; UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... - Page 40 C P(max) UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 40 of 54...
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Page 41: Fig 17. P(Max) As A Function Of Bus Capacitance
(Fig 19). In both examples the optional backup supply is realized using a 1 F capacitor. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 42: Fig 18. Application Diagram 1, I C-Bus Interface
RTC. If the outputs need to be used to switch signals connected to a higher potential, it is necessary to use an external transistor. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 42 of 54... -
Page 43: Fig 20. General Countdown Timer Behaviour
INT is set to pulsed mode Fig 20. General countdown timer behaviour UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 43 of 54... - Page 44 UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 44 of 54...
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Page 45: Timing Requirements For I
RTC has been drawn. In Fig 22 a sequence of events after a read operation starts is depicted. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 45 of 54... -
Page 46: Fig 21. Block Diagram I C Interface And Time Counters
The exact sequence of events is depicted in Fig 22. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 46 of 54... -
Page 47: Fig 22. Sequence Of Events (Example Read)
STOP condition occurs. Now still the errors mentioned in the introduction of this UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 48: Troubleshooting
RTC doesn’t work due to problems with the serial bus. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 48 of 54... -
Page 49: No Communication Via I
C-bus interface is reset. Thus for this device a second option of releasing the I bus is available. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 49 of 54... -
Page 50: Wrong Time And Date, Wrong Clock Speed
6. Epson Toyocom, Crystal Devices Catalogue “The crystal master”, 2007. 7. Micro Crystal, Product Catalog Quartz Crystals 2008. UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 50 of 54... -
Page 51: Legal Information
The English version shall prevail in case of any discrepancy between the translated and English versions. In no event shall NXP Semiconductors be liable for any indirect, incidental, punitive, special or consequential damages (including - without limitation - Evaluation products —... -
Page 52: Table Of Contents
Fig 22. Sequence of events (example READ) .... 47 UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015 52 of 54... -
Page 53: List Of Tables
Table 11. First period delay for timer counter value n ..44 UM10301 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved. User manual Rev. 2.1 — 23 July 2015... -
Page 54: Contents
Checking for oscillation ........48 Please be aware that important notices concerning this document and the product(s) described herein, have been included in the section 'Legal information'. © NXP Semiconductors N.V. 2015. All rights reserved. For more information, please visit: http://www.nxp.com...
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