PCF8563PN datasheet by NXP Semiconductors

PCF8563PN Frequently Asked Questions (FAQs)

• What is the recommended power-on reset (POR) timing for the PCF8563PN?
  The recommended POR timing is to keep the VCC pin above 1.5V for at least 100ms to ensure a proper reset.
• How do I handle the clock calibration for the PCF8563PN?
  The PCF8563PN has an internal clock calibration circuit. To calibrate the clock, set the CAL bit in the Control Register 2 (CR2) to 1, and then write the desired calibration value to the Calibration Register (CALR). The calibration value is a 7-bit signed value, with a range of -64 to +63.
• What is the purpose of the VBAT pin on the PCF8563PN?
  The VBAT pin is used to connect a battery or a supercapacitor to provide power to the internal clock and SRAM when the main power supply (VCC) is absent or low. This allows the device to maintain its clock and data during power failures.
• How do I use the alarm function on the PCF8563PN?
  To use the alarm function, set the Alarm Enable bit (AE) in the Control Register 1 (CR1) to 1, and then set the desired alarm time and date in the Alarm Registers (ALR1-ALR4). When the alarm time matches the current time, the AF flag in the Status Register (SR) will be set, and an interrupt will be generated if enabled.
• What is the maximum clock frequency that can be used with the PCF8563PN?
  The maximum clock frequency that can be used with the PCF8563PN is 32.768 kHz, which is the typical frequency of a quartz crystal oscillator.