关于PCF8563 Real-time clock 推荐负载电容及晶振参数，晶诺威科技介绍如下：

Fosc = 32.768 kHz; quartz Rs = 40 kΩ; CL = 8 pF

NOTE:

By evaluating the average capacitance necessary for the application layout, a fixed capacitor can be used. The frequency is best measured via the 32.768 kHz signal available after power-on at pin CLKOUT. The frequency tolerance depends on the quartz crystal tolerance, the capacitor tolerance and the device-to-device tolerance.

关于PCF8563（Real-time clock/calendar）

The PCF8563 is a CMOS Real-Time Clock (RTC) and calendar optimized for low power consumption. A programmable clock output, interrupt output, and voltage-low detector arealso provided. All addresses and data are transferred serially via a two-line bidirectional I2C-bus. Maximum bus speed is 400 kbit/s. The register address is incremented automatically after each written or read data byte.

PCF8563是一款专为低功耗设计的CMOS实时时钟（RTC）和日历芯片。它具备可编程时钟输出、中断输出和电压低检测功能。所有地址和数据均通过双向I2C总线以串行方式传输。总线速度为400 kbit/s。每次写入或读取数据字节后，寄存器地址会自动递增。

Features and benefits 特点与优势

• Provides year, month, day, weekday, hours, minutes, and seconds based on a 32.768 kHz quartz crystal
• Century flag
• Clock operating voltage: 1.0 V to 5.5 V at room temperature
• Low backup current; typical 0.25uA at VDD = 3.0 V and Tamb = 25℃
• 400 kHz two-wire I2C-bus interface (at VDD = 1.8 V to 5.5 V)
• Programmable clock output for peripheral devices (32.768 kHz, 1.024 kHz, 32 Hz, and
  1 Hz)
• Alarm and timer functions
• Integrated oscillator capacitor
• Internal Power-On Reset (POR)
• I2C-bus slave address: read A3h and write A2h
• Open-drain interrupt pin

Applications主要应用

• Mobile telephones 手机
• Portable Electronic instruments 手持电子设备
• Electronic metering 电子计量仪
• Battery powered products 电池供电产品