Page-1
Aug. 1998
Serial RTC with Alarm and Timer
RTC
-
4573
Built-in frequency adjusted 32.768KHz crystal oscillator
Serial interface that can be controlled through three signal lines
Week , Day , hour , and minute alarm interrupt functions
Interval timer interrupt function that can be set with an interval ranging from 1/4096th of a second to 255minutes
Dual dedicated interrupt outputs for software maskable alarms and for timers
Functions that detect halting of crystal oscillation, and when the time is being updated
Automatic leap year compensation function
Wide interface voltage range, from 1.6 to 5.5V
Wide timing voltage range, from 1.6 to 5.5V
Low current consumption : 0.5
m
A/3V (typ.)
Small SOP package suited for high-density mounting
n
n
n
n
Overview
This module is a serial interface-type real-time clock with a crystal oscillator on chip. This module includes clock
and calendar circuitry (from seconds to years) with automatic leap year compensation, alarms, and timer interrupt
functions, as well as functions that detect when oscillation is halted, the time is being updated. The serial
interface permits control through three signal lines, keeping the number of ports required on the system side to a
minimum. Because the small SOP package can be used in high-density mounting, this module is ideal for
portable telephones, hand-held terminals, and other compact electronic equipment.
n
n
n
n
Block Diagram
INTERRUPTS
CONTROLLER
ALARM
REGISTER
OSC
/ TIRQ
BUS
INTERFACE
CIRCUIT
SHIFT REGISTER
DATA
CLK
C E0
32.768KHz
CONTROL
REGISTER
DIVIDER
CLOCK and
CALENDAR
CONTROL LINE
/ AIRQ
C E1
OUTPUT
CONTROLLER
FOUT
TIMER
REGISTER
Page-2
Aug.1998
n
n
n
n
Pin Connection
2.
3
4
5
6
1.
7.
9
8.
GND
DD
V
N.C
N.C
N.C
#1
#9
#10
#18
17
16
15
14
13
18
12
10
11.
CLK
DATA
N.C
/ AIRQ
CE1
N.C
N.C
N.C
N.C
/ TIRQ
N.C
FOUT
CE0
Symbol
Pin-No.
I / O
Function
CE1
5
Input
Chip enable 1 input pin.
This terminal has pull-down resistor built-in. Access to this RTC is possible in
"H" level both CE0,CE1 terminal. FOUT terminal can output frequency when
inputs "H" level into this terminal regardless of state of CE0 terminal. FOUT
terminal is high impedance state in input "L" level.
DATA
6
Bi-
directional
This I/O pin is used to for setting write mode/read mode, for writing an
address, and for reading and writing data. This pin functions either as an
input pin or an output pin, according to the write mode/read mode setting
made in the first 8 bits of input data following the rising edge of the CE input.
CLK
7
Input
Shift clock input pin. In write mode, the data is read from the DATA pin at
the rising edge of the CLK signal; in read mode, the data is output from the
DATA pin at the rising edge of the CLK signal.
GND
9
-
Connect to the negative (ground) line of the power supply.
/ TIRQ
10
Output
Open drain interrupt output pin for the interval timer.
/ AIRQ
11
Output
Output Open drain interrupt output pin for alarms.
CE0
12
Input
Chip enable 0 input pin.
When high, access to the internal registers is enabled. While low, the
DATA pin goes to high impedance. When the CE pin is set low, the fr, TEST,
and RESET bits are forcibly cleared to "0".Set this pin low when turning the
power on, when the device is not to be accessed, and when using the
backup power supply. This pin does not affect FOUT terminal.
FOUT
13
Output
Frequency output terminal. Frequency is selectable by software.
V
DD
14
-
Connect to the positive line of the power supply.
Access is possible between 1.6 and 5.5V
N.C.
1,2,3,
4,8,
15,16,
17,18
Although these pins are not connected internally, they should always be left
open in order to obtain the most stable oscillation possible.
* Always connect a passthrough capacitor of at least 0.1
m
F as close as possible between V
DD
and GND.
Page-3
Aug.1998
n
Electrical Characteristics
1. Absolute Maximum Ratings
Description
Symbol
Conditions
Rated values
Unit
Power supply Voltage
V
DD
-
-0.3 to +7.0
V
Input Voltage
V
IN1
input pins
GND-0.3 to V
DD
+0.3
V
Output Voltage
V
OUT1
/ TIRQ,/ AIRQ
-0.3 to +8.0
V
V
OUT2
FOUT,DATA
GND-0.3 to V
DD
+0.3
Temperature
T
STG
-
-55 to +125
C
2. Operating Condition
Item
Symbol
Conditions
MIN.
MAX.
Unit
Supply Voltage
V
DD
-
1.6
5.5
V
Data Holding Voltage
V
CLK
-
1.6
5.5
V
Operating Temperature Range
T
OPR
C
3. Frequency Characteristics
Item
Symbol
Conditions
Specifications
Unit
Frequency accuracy
f / fo
Ta=25
C,V
DD
=3V
5 23 *
ppm
Oscillator start up time
t
STA
Ta=25
C,V
DD
=1.6V
3 (MAX)
sec
Temperature characteristics
-10 to 70
C 25
C(Typ)
+10 / -120
ppm
Voltage characteristics
Ta=25
C,V
DD
=1.6 to 5.5V
2.0
ppm / V
* Monthly error of about 1 minute
4. DC Characteristics
(V
DD
=1.6 to 5.5V,Ta=-40 to 85
C )
Description
Symbol
Conditions
MIN.
TYP.
MAX.
Unit
Standby current 1
I
DD1
V
DD
=5V
CE0,CE1=GND
-
1.0
2.0
m
A
Standby current 2
I
DD2
V
DD
=3V
CE0,CE1=GND
-
0.5
1.0
m
A
Input Voltage
VIH
CE0,CE1
0.8V
DD
-
V
DD
V
VIL
CLK,DATA pins
0
-
0.2V
DD
V
Input leakage current
I
LK
VI=V
DD
or GND
CLK pins
-0.5
-
0.5
m
A
PulIdown R 1
R
DWN1
V
DD
=5V
75
150
300
k W
PulIdown R 2
R
DWN2
V
DD
=3V
CE0,CE1 pins
150
300
600
k W
V
OH1
V
DD
=5V
I
OH
=-1mA
4.5
5.0
V
V
OH2
V
DD
=3V
DATA,FOUT pins
2.0
3.0
V
Output voltage 1
V
OH3
V
DD
=3V
I
OH
=-100
m
A
DATA,FOUT pins
2.9
3.0
V
V
OL1
V
DD
=5V
I
OL
=1mA
GND+0.5
V
V
OL2
V
DD
=3V
DATA,FOUT pins
GND+0.8
V
V
OL3
V
DD
=3V
I
OL
=100
m
A
DATA,FOUT pins
GND+0.1
V
Output voltage 2
V
OL4
V
DD
=5V
I
OL
=1mA
GND+0.25
V
V
OL5
V
DD
=3V
/ AIRQ,/ TIRQ pins
GND+0.4
V
Leakage current
I
OZ
V
O
=GND or V
DD
DATA,/ AIRQ,/ TIRQ pins
-0.5
0.5
m
A
-
+85
Page-4
Aug.1998
5. AC Characteristics
( CL=50pF,Ta=-40 to 85
)
V
DD
=3.0V10%
V
DD
=5.0V10%
Description
Symbol
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
Unit
CLK clock cycle
t
CLK
1200
600
ns
CLK H Pulse Width
t
WH
600
-
-
300
-
-
ns
CLK L Pulse Width
t
WL
600
-
-
300
-
-
ns
CE setup time
t
CS
300
-
-
150
-
-
ns
CE hold time
t
CH
400
-
-
200
-
-
ns
CE recovery time
t
CR
600
-
-
300
-
-
ns
CLK hold time
t
CKH
100
-
-
50
-
-
ns
Write DATA in setup time
t
DS
50
-
-
50
-
-
ns
Write DATA in hold time
t
DH
50
-
-
50
-
-
ns
Read DATA in delay time
t
RD
0
-
400
0
-
200
ns
Output disable delay time
t
RZ
-
-
200
-
-
100
ns
rise and fall time
t
RF
-
-
40
-
-
20
ns
FOUT duty ratio
( 32.768kHz output )
Duty
35
-
65
40
-
60
%
CLK
C E
CS
t
WL
t
WH
t
CH
t
CKH
t
CR
t
50%
50%
Write Mode
ReadMode
CLK
DATA
CLK
DATA
C E
Hi-Z
DS
t
DH
t
RF
t
RF
t
RZ
t
RD
t
C E
CS
t
%
50
%
50
%
50
%
50
%
90
%
10
%
90
%
10
%
50
%
50
C
Page-5
Aug.1998
n
Register Table
Address
Function
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
0
Sec
fos
40
20
10
8
4
2
1
1
Min
fr
40
20
10
8
4
2
1
2
Hour
fr
*
20
10
8
4
2
1
3
Week
fr
6
5
4
3
2
1
0
4
Day
fr
*
20
10
8
4
2
1
5
Month
fr
*
*
10
8
4
2
1
6
Year
80
40
20
10
8
4
2
1
7
Minutes Alarm
AE
40
20
10
8
4
2
1
8
Hours Alarm
AE
*
20
10
8
4
2
1
9
Week Alarm
AE
6
5
4
3
2
1
0
A
Day Alarm
AE
*
20
10
8
4
2
1
B
FOUT control
FE
*
FD4
FD3
*
FD2
FD1
FD0
C
Timer interrupt control
TE
*
TD1
TD0
*
*
*
*
D
Count Down Timer
128
64
32
16
8
4
2
1
E
Control 1
*
*
*
TI/TP
AF
TF
AIE
TIE
F
Control 2
*
TEST
STOP
RESET
HOLD
*
*
*
1.1 Timekeeping/calendar registers (register 0 to register 6)
The data in these registers is BCD format. For example, "0101 1001" represents 59 seconds. In addition, the
"*" mark in the register table means that the register is readable and writable, and can be used as RAM. Time is
kept in the 24-hour format.
Writing to a bit marked with an asterisk ("*") is permitted; such bits can be used as RAM. When the alarm and
timer functions are not used, registers 7 to A can be used as 8-bit memory registers, and registers C and D can
be used as 7-bit memory registers.
Year register and leap years
A leap year is detected by dividing the two BCD digits of the year register by four; if the remainder is zero, the
year is a leap year. Therefore, leap years can be automatically determined whether the year is numbered
according to the western calendar or the Japanese calendar (year of Heisei).
Day of the week
The day of the week register uses 7 bits, from 0 to 6; the meanings of the bits are shown in the table below. Do
not set more than one bit to "1" at any one time.
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
day of week
0
0
0
0
0
0
1
Sunday
0
0
0
0
0
1
0
Monday
0
0
0
0
1
0
0
Tuesday
0
0
0
1
0
0
0
Wednesday
0
0
1
0
0
0
0
Thursday
0
1
0
0
0
0
0
Friday
1
0
0
0
0
0
0
Saturday
fos ( OSC Flag )
This flag uses it for a monitor of battery listing degradation with the binary digit which that oscillation stopped is
set at. Oscillation stopping shows "1", and it is cleared by writing in "0". But fo flag can't write in "0" when
oscillation stopped. And fo can write in "1", but don't write in it. Other binary digit (HOLD,STOP,RESET) doesn't
receive affect even in case of "1".
fr ( READ Flag )
It is the binary digit that turn into "1" when CE was input, and carry occurred during "H" for 1 second. The distinction
that carry to a figure rose during (CE input ="H" during readout of register in an indicator by this for 1 second is
possible. When fr was "1", I need to read register in all indicators once again.
PDF 
ZIP