Philips PCF8563P, PCF8563T, PCF8563TS Datasheet

PCF8563

Real-time clock/calendar

16 April 1999 Product specification

1. General description

The PCF8563 is a CMOS real-time clock/calendar optimized for low power
consumption. A programmableclockoutput,interruptoutputandvoltage-low detector
are also provided. All address and data are transferred serially via a two-line
bidirectional I2C-bus. Maximum bus speed is 400 kbits/s. The built-in word address
register is incremented automatically after each written or read data byte.

2. Features

■ Provides year, month, day, weekday, hours, minutes and seconds based on

32.768 kHz quartz crystal

■ Century flag

■ Wide operating supply voltage range: 1.0 to 5.5 V

■ Low back-up current; typical 0.25 µA at VDD= 3.0 V and T

■ 400 kHz two-wire I2C-bus interface (at VDD= 1.8 to 5.5 V)

■ Programmable clock output for peripheral devices: 32.768 kHz, 1024 Hz,

32 Hz and 1 Hz

■ Alarm and timer functions

■ Voltage-low detector

■ Integrated oscillator capacitor

■ Internal power-on reset

■ I2C-bus slave address: read A3H; write A2H

■ Open drain interrupt pin.

amb

=25°C

3. Applications

■ Mobile telephones

■ Portable instruments

■ Fax machines

■ Battery powered products.

Philips Semiconductors

PCF8563

Real-time clock/calendar

4. Quick reference data

Table 1: Quick reference data

Symbol Parameter Conditions Min Max Unit

V

DD

I

DD

T

amb

T

stg

supply voltage operating mode I2C-bus inactive; T

2

C-bus active; f

I

= −40 to +85 °C

T

amb

supply current; timer and CLKOUT
disabled

f

= 400 kHz - 800 µA

SCL

= 100 kHz - 200 µA

f

SCL

= 0 Hz; T

f

SCL

V
V

DD
DD

amb

= 5 V - 550 nA

= 2 V - 450 nA
operating ambient temperature −40 +85 °C
storage temperature −65 +150 °C

=25°C 1.0 5.5 V

amb

= 400 kHz;

SCL

1.8 5.5 V

=25°C

5. Ordering information

Table 2: Ordering information

Type number Package

Name Description Version

PCF8563P DIP8 plastic dual in-line package; 8 leads (300 mil) SOT97-1
PCF8563T SO8 plastic small outline package; 8 leads; body width 3.9 mm SOT96-1
PCF8563TS TSSOP8 plastic thin shrink small outline package; 8 leads; body width 3.0 mm SOT505-1

6. Block diagram

DIVIDER

LOGIC

CLKOUT

7

CONTROL/STATUS 1

1 Hz

CONTROL/STATUS 2
SECONDS/VL
MINUTES
HOURS
DAYS
WEEKDAYS
MONTHS/CENTURY
YEARS
MINUTE ALARM
HOUR ALARM
DAY ALARM
WEEKDAY ALARM
CLKOUT CONTROL
TIMER CONTROL
TIMER

0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F

handbook, full pagewidth

OSCI

OSCO

INT

V

SS

V

DD

SCL

SDA

1
2
3
4
8

6
5

OSCILLATOR

32.768 kHz

VOLTAGE

DETECTOR

OSCILLATOR

MONITOR

I2C-BUS

INTERFACE

POR

CONTROL

ADDRESS
REGISTER

MGM662

Fig 1. Block diagram.

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Product specification 16 April 1999 2 of 30

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Philips Semiconductors

7. Pinning information

7.1 Pinning

PCF8563

Real-time clock/calendar

handbook, halfpage

OSCI

INT

V

SS

1

PCF8563P

2

PCF8563T

3

PCF8563TS

4

Fig 2. Pin configuration.

handbook, halfpage

1

OSCI

V

INT

SS

2

3

4

OSCO

PCF8563

Fig 3. Device diode protection diagram.

MGR885

8
7
6
5

MGR886

V

CLKOUTOSCO
SCL
SDA

8

7

6

5

DD

V

DD

CLKOUT

SCL

SDA

7.2 Pin description

Table 3: Pin description

Symbol Pin Description

OSCI 1 oscillator input
OSCO 2 oscillator output
INT 3 interrupt output (open-drain; active LOW)
V

SS

SDA 5 serial data I/O
SCL 6 serial clock input
CLKOUT 7 clock output (open-drain)
V

DD

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Product specification 16 April 1999 3 of 30

4 ground

8 positive supply

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Philips Semiconductors

8. Functional description

The PCF8563 contains sixteen 8-bit registers with an auto-incrementing address
register, an on-chip 32.768 kHz oscillator with an integrated capacitor, a frequency
divider which provides the source clock for the Real-Time Clock (RTC), a
programmable clock output, a timer, an alarm, a voltage-low detector and a 400 kHz
I2C-bus interface.

All 16 registers 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/or status registers. The memory addresses 02H through 08H are
used as counters for the clock function (seconds up to year counters). Address
locations 09H through 0CH contain alarm registers which define the conditions for an
alarm. Address 0DH controls the CLKOUT output frequency. 0EH and 0FH are the
timer control and timer registers, respectively.

The Seconds, Minutes, Hours, Days, Months, Years as well as the Minute alarm,
Hour alarm and Day alarm registers are all coded in BCD format. The Weekdays and
Weekday alarm register are not coded in BCD format.

PCF8563

Real-time clock/calendar

When one of the RTC registers is read the contents of all counters are frozen.
Therefore, faulty reading of the clock/calendar during a carry condition is prevented.

8.1 Alarm function modes

By clearing the MSB (bit AE = Alarm Enable) of one or more of the alarm registers,
the corresponding alarm condition(s) will be active. In this way an alarm can be
generated from once per minute up to once per week. The alarm condition sets the
alarm flag, AF (bit 3 of Control/Status 2 register). The asserted AF can be used to
generate an interrupt (INT). Bit AF can only be cleared by software.

8.2 Timer

The 8-bit countdown timer (address 0FH) is controlled by the Timer Control register
(address 0EH; see Table 25). The Timer Control register selects one of 4 source
clock frequencies for the timer (4096, 64, 1, or1⁄60Hz), and enables/disables the
timer. The timer counts down from a software-loaded 8-bit binary value. At the end of
every countdown, the timer sets the timer flag TF (see Table 7). The timer flag TF can
only be cleared by software. The asserted timer flag TF can be used to generate an
interrupt (INT). The interrupt may be generated as a pulsed signal every countdown
period or as a permanently active signal which follows the condition of TF. TI/TP (see

Table 7) is used to control this mode selection. When reading the timer, the current

countdown value is returned.

8.3 CLKOUT output

A programmable square wave is availableat the CLKOUT pin. Operation is controlled
by the CLKOUT frequency register (address 0DH; see Table 23). Frequencies of

32.768 kHz (default), 1024, 32 and 1 Hz can be generated for use as a system clock,
microcontroller clock, input to a charge pump, or for calibration of the oscillator.
CLKOUT is an open-drain output and enabled at power-on. If disabled it becomes
high-impedance.

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8.4 Reset

The PCF8563 includes an internal reset circuit which is active whenever the oscillator
is stopped. In the reset state the I2C-bus logic is initialized and all registers, including
the address pointer, are cleared with the exception of bits FE, VL, TD1, TD0, TESTC
and AE which are set to logic 1.

8.5 Voltage-low detector and clock monitor

PCF8563

Real-time clock/calendar

The PCF8563 has an on-chip voltage-low detector. When VDD drops below V
VL bit (Voltage Low, bit 7 in the Seconds register) is set to indicate that reliable
clock/calendar information is no longer guaranteed. The VL flag can only be cleared
by software.

The VL bit is intended to detect the situation when VDD is decreasing slowly for
example under battery operation. Should VDDreach V

before power is re-asserted

low

then the VL bit will be set. This will indicate that the time may be corrupted.

handbook, halfpage

V

DD

V

low

Fig 4. Voltage-low detection.

period of battery
operation

VL set

MGR887

normal power
operation

t

8.6 Register organization

low

the

Table 4: Registers overview

Bit positions labelled as ‘−’are not implemented; those labelled with ‘0’ should always be written with logic 0.

Address Register name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

00H Control/Status 1 TEST1 0 STOP 0 TESTC 0 0 0
01H Control/Status 2 0 0 0 TI/TP AF TF AIE TIE
0DH CLKOUT frequency FE −−−−−FD1 FD0
0EH Timer control TE −−−−−TD1 TD0
0FH Timer countdown

value

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Product specification 16 April 1999 5 of 30

<timer countdown value>

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Philips Semiconductors

PCF8563

Real-time clock/calendar

Table 5: BCD formatted registers overview

Bit positions labelled as ‘−’are not implemented.

Address Register name BCD format tens nibble BCD format units nibble

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

3

2

02H Seconds VL <seconds 00 to 59 coded in BCD>
03H Minutes − <minutes 00 to 59 coded in BCD>
04H Hours −− <hours 00 to 23 coded in BCD>
05H Days −− <days 01 to 31 coded in BCD>
06H Weekdays −−−−− <weekdays 0 to 6 >
07H Months/Century C −− <months 01 to 12 coded in BCD>
08H Years <years 00 to 99 coded in BCD>
09H Minute alarm AE <minute alarm 00 to 59 coded in BCD>
0AH Hour alarm AE − <hour alarm 00 to 23 coded in BCD>
0BH Day alarm AE − <day alarm 01 to 31 coded in BCD>
0CH Weekday alarm AE −−−− <weekday alarm 0 to 6 >

2

2

1

2

0

2

3

2

2

2

1

2

0

2

[1]

[1]

[1] Not coded in BCD.

8.6.1 Control/Status 1 register

Table 6: Control/Status 1 register bits description (address 00H)

Bit Symbol Description

7 TEST1 TEST1 = 0; normal mode.

TEST1 = 1; EXT_CLK test mode; see Section 8.7.

5 STOP STOP = 0; RTC source clock runs.

STOP = 1; all RTC divider chain flip-flops are asynchronously set
to logic 0; the RTC clock is stopped (CLKOUT at 32.768 kHz is still
available).

3 TESTC TESTC = 0; power-on reset override facility is disabled (set to logic 0

for normal operation).
TESTC = 1; power-on reset override is enabled.

6, 4, 2 to 0 0 By default set to logic 0.

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8.6.2 Control/Status 2 register

Table 7: Description of Control/Status 2 register bits description (address 01H)

Bit Symbol Description

7 to 5 0 By default set to logic 0.
4 TI/TP TI/TP = 0: INT is active when TF is active (subject to the status of TIE).

3 AF When an alarm occurs, AF is set to logic 1. Similarly, at the end of a
2TF

1 AIE Bits AIE and TIE activate or deactivate the generation of an interrupt
0 TIE

PCF8563

Real-time clock/calendar

TI/TP = 1: INT pulses active according to Table 8 (subjectto the status
of TIE). Note that if AF and AIE are active then INT will be permanently
active.

timer countdown, TF is set to logic 1. These bits maintain their value
until overwritten by software. If both timer and alarm interrupts are
required in the application, the source of the interrupt can be
determined by reading these bits. To prevent one flag being
overwritten while clearing another, a logic AND is performed during a
write access. See Table 9 for the value descriptions of bits AF and TF.

when AF or TF is asserted, respectively.The interrupt is the logical OR
of these two conditions when both AIE and TIE are set.

AIE = 0: alarm interrupt disabled; AIE = 1: alarm interrupt enabled.
TIE = 0: timer interrupt disabled; TIE = 1: timer interrupt enabled.

Table 8:

Source clock (Hz) INT

4096
64
1

1

⁄

60

[1] TF and INT become active simultaneously.
[2] n = loaded countdown timer value. Timer stopped when n = 0.

INT operation (bit TI/TP = 1)

[1]

period (s)

[2]

n

=1 n>1

1

⁄

8192

1

⁄

128

1

⁄

64

1

⁄

64

Table 9: Value descriptions for bits AF and TF

R/W Bit: AF Bit: TF

Value Description Value Description

Read 0 alarm flag inactive 0 timer flag inactive

1 alarm flag active 1 timer flag active

Write 0 alarm flag is cleared 0 timer flag is cleared

1 alarm flag remains unchanged 1 timer flag remains unchanged

1

⁄

4096

1

⁄

64

1

⁄

64

1

⁄

64

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8.6.3 Seconds, Minutes and Hours registers

Table 10: Seconds/VL register bits description (address 02H)

Bit Symbol Description

7 VL VL = 0: reliable clock/calendar information is guaranteed;

6 to 0 <seconds> These bits represent the current seconds value coded in BCD

Table 11: Minutes register bits description (address 03H)

Bit Symbol Description

7 − not implemented
6 to 0 <minutes> These bits represent the current minutes value coded in BCD

Table 12: Hours register bits description (address 04H)

Bit Symbol Description

7 to 6 − not implemented
5 to 0 <hours> These bits represent the current hours value coded in BCD format;

PCF8563

Real-time clock/calendar

VL = 1: reliable clock/calendar information is no longer
guaranteed.

format; value = 00 to 59.
Example: <seconds> = 101 1001, represents the value 59 s.

format; value = 00 to 59.

value=00to23.

8.6.4 Days, Weekdays, Months/Century and Years registers

Table 13: Days register bits description (address 05H)

Bit Symbol Description

7 to 6 − not implemented
5 to 0 <days> These bits represent the current day value coded in BCD format;

value = 01 to 31.
The PCF8563 compensates for leap years by adding a 29th day to

February if the year counter contains a value which is exactly
divisible by 4, including the year ‘00’.

Table 14: Weekdays register bits description (address 06H)

Bit Symbol Description

7 to 3 − not implemented
2 to 0 <weekdays> These bits represent the current weekday value 0 to 6;

see Table 15.
These bits may be re-assigned by the user.

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Table 15: Weekday assignments

Day Bit 2 Bit 1 Bit 0

Sunday 0 0 0
Monday 0 0 1
Tuesday 0 1 0
Wednesday 0 1 1
Thursday 1 0 0
Friday 1 0 1
Saturday 1 1 0

Table 16: Months/Century register bits description (address 07H)

Bit Symbol Description

7 C Century bit. C = 0; indicates the century is 20xx.

6to5 − not implemented
4 to 0 <months> These bits represents the current month value coded in BCD format;

PCF8563

Real-time clock/calendar

C = 1; indicates the century is 19xx. ‘xx’ indicates the value held in the
Years register; see Table 18.

This bit is toggled when the Years register overflows from 99 to 00.
These bits may be re-assigned by the user.

value = 01 to 12; see Table 17.

Table 17: Month assignments

Month Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

January00001
February00010
March 00011
April 00100
May 00101
June 00110
July 00111
August 01000
September 01001
October 10000
November 10001
December 10010

Table 18: Years register bits description (address 08H)

Bit Symbol Description

7 to 0 <years> This register represents the current year value coded in BCD

format; value = 00 to 99.

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