The PCF85163 is an NXP device that comes in a SOIC8 package. It is an RTC (Real-Time Clock), which is identical to the PCF8563.

The PCF85163 has sixteen 8-bit registers with auto-incrementing register addresses. It also has a 32.768 kHz oscillator on-chip with one integrated capacitor, a frequency divider that serves as the source clock for the RTC and calendar, a programmable clock output, a timer, an alarm, a voltage-low detector, and a 400 kHz I2C-bus interface.

While not all bits are implemented, all 16 registers are planned as addressable 8-bit parallel registers. Control and/or status registers are utilized in the first two registers (memory addresses 00h and 01h). The addresses 02h through 08h are utilized as clock function counters (seconds up to years counters). Alarm registers are located at address positions 09h through 0Ch and establish the requirements for an alert. The frequency of the CLKOUT output is controlled by address 0Dh. The timer control and timer registers are represented by 0Eh and 0Fh, respectively.

Seconds, Minutes, Hours, Days, Months, and Years are all coded in Binary Coded Decimal (BCD) format, as are the Minute alarm, Hour alarm, and Day alarm registers.

The contents of all time counters are frozen when one of the RTC registers is written or read. This avoids incorrect clock and calendar writing or reading during a carry state.