NXP Semiconductors UM10301 PCF2123 User Manual
NXP Semiconductors Hardware
UM10301
User Manual for NXP Real Time Clocks PCF85x3, PCA8565
and PCF2123, PCA2125
Rev. 01 — 23 December 2008
User manual
Document information
Info
Content
Keywords
PCF8563, PCF8573, PCF8583, PCF8593, PCA8565, PCF2123,
PCA2125, PCF2120, RTC, real time clock, timekeeping, crystal,
32.768 kHz, backup.
Abstract
This application note aims to assist a user of above mentioned Real Time
Clocks in achieving succesful 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 PCA2125
have been taken into account.
This manual is related to the following products:
Table of contents
Document Outline
- 1. Introduction
- 2. Features
- 3. Comparison
- 4. Power-on reset (POR)
- 5. Voltage-low detector
- 6. Oscillator
- 7. Crystal and crystal selection
- 8. Capacitors and capacitor selection
- 9. Accuracy
- 10. Oscillator tuning
- 11. Century and leap year, Daylight Saving Time
- 12. Initialization and setting of alarm and timer
- 13. Backup power supply
- 14. PCB layout guidelines
- 15. Partial circuit switch down
- 16. Hints to keep power consumption low
- 17. First period inaccuracy when using the timer
- 18. Timing requirements for I2C read and write
- 19. Troubleshooting
- 20. References
- 21. Legal information
- 22. Contents