PCF85063TP datasheet(4/52 Pages) NXP

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PCF85063TP

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Product data sheet

Rev. 4 — 6 May 2015

4 of 52

NXP Semiconductors

PCF85063TP

Tiny Real-Time Clock/calendar

Functional description

The PCF85063TP contains 11 8-bit registers with an auto-incrementing register address,

an on-chip 32.768 kHz oscillator with integrated capacitors, a frequency divider which

provides the source clock for the Real-Time Clock (RTC) and calender, and an I2C-bus

interface with a maximum data rate of 400 kbit/s.

The built-in address register will increment automatically after each read or write of a data

byte up to the register 0Ah. After register 0Ah, the auto-incrementing will wrap around to

address 00h (see Figure 3).

All 11 registers (see Table 5) are designed as addressable 8-bit parallel registers although

not all bits are implemented. The first two registers (memory address 00h and 01h) are

used as control and status register. The register at address 02h is an offset register

allowing the fine-tuning of the clock; and at 03h is a free RAM byte. The addresses 04h

through 0Ah are used as counters for the clock function (seconds up to years counters).

The Seconds, Minutes, Hours, Days, Months, and Years registers are all coded in Binary

Coded Decimal (BCD) format. When one of the RTC registers is written or read, the

contents of all time counters are frozen. Therefore, faulty writing or reading of the clock

and calendar during a carry condition is prevented.

Fig 3.

Handling address registers

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