MQ372-01
Application
Manua
l
Real Time Clock Module
RX-8581SA/JE/NB
Model
RX-8581SA
RX-8581JE
RX-8581NB
Product Number
Q41858151000200
Q41858171000200
Q41858191000200
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NOTICE
• The material is subject to change without notice.
• Any part of this material may not be reproduced or duplicated in any form or any means without the
written permission of Seiko Epson.
• The information, applied circuit, program, using way etc., written in this material is just for reference.
Seiko Epson does not assume any liability for the occurrence of infringing any patent or copyright of third
party. This material does not authorize the licence for any patent or intellectual property rights.
• Any product described in this material may contain technology or the subject relating to strategic
products under the control of the Foreign Exchange and Foreign Trade Law of Japan and may require an
export licence from the Ministry of International Trade and industry or other approval from another
government agency.
• The products (except for some product for automotive applications) listed up on this material are designed
to be used with ordinary electronic equipment (OA equipment, AV equipment, communications equipment,
measuring instruments etc). Seiko Epson does not assume any liability for the case using the products with
the appoication required high reliability or safety extremely (such as aerospace equipment etc).
When intending to use any our product with automotive application and the other application than
ordinary electronic equipments as above, please contact our sales representatives in advance.
RX - 8581 SA
/
JE
/
NB
Contents
1. Overview
.................................................................................................................. 1
2. Block Diagram
....................................................................................................... 1
3. Terminal description
............................................................................................ 2
3.1. Terminal connections
.............................................................................................................. 2
3.2. Pin Functions
............................................................................................................................. 2
4. Absolute Maximum Ratings
.............................................................................. 3
5. Recommended Operating Conditions
.......................................................... 3
6. Frequency Characteristics
................................................................................ 3
7. Electrical Characteristics
................................................................................... 3
7.1. DC characteristics
........................................................................................................................ 3
7.2. AC Characteristics
................................................................................................................... 4
8. Use Methods
.......................................................................................................... 5
8.1. Overview of Functions
............................................................................................................ 5
8.2. Description of Registers
......................................................................................................... 6
8.3. Fixed-cycle Timer Interrupt Function
............................................................................... 13
8.4. Time Update Interrupt Function
......................................................................................... 16
8.5. Alarm Interrupt Function
...................................................................................................... 18
8.6. Reading/Writing Data via the I
2
C Bus Interface
........................................................... 21
8.7. Backup and Recovery
........................................................................................................... 25
8.8. Connection with Typical Microcontroller
......................................................................... 25
9. External Dimensions / Marking Layout
....................................................... 26
10. Reference Data
................................................................................................ 27
RX - 8581 SA
/
JE
/
NB
I
2
C-Bus Interface Real-time Clock Module
RX - 8581 SA
/
JE
/
NB
•
•
•
•
•
•
•
•
•
•
•
Features built-in 32.768-kHz crystal oscillator, frequency adjusted
2
Supports I C-Bus's high speed mode (400 kHz)
Alarm interrupt function for day, date, hour, and minute settings
Fixed-cycle timer interrupt function
(Seconds, minutes)
Time update interrupt function
(FOE and FOUT pins)
32.768-kHz output with OE function
(from 2000 to 2099)
Auto correction of leap years
Wide interface voltage range: 1.8 V to 5.5 V
Wide time-keeping voltage range:1.6 V to 5.5 V
Low current consumption: 0.45
µ
A /3 V (Typ.)
Compact package (NB: SON−22 pin PKG)
The I C-Bus is a trademark of PHILIPS ELECTRONICS N.V.
2
1. Overview
This module is an I C bus interface-compliant real-time clock which includes a 32.768-kHz crystal oscillator.
In addition to providing a calendar (year, month, date, day, hour, minute, second) function and a clock counter
function, this module provides an abundance of other functions including an alarm function, fixed-cycle timer
function, time update interrupt function, and 32.768-kHz output function.
The devices in this module are fabricated via a C-MOS process for low current consumption, which enables
long-term battery back-up.
All of these many functions are implemented in a thin, compact SON package, which makes it suitable for
various kinds of mobile telephones and other small electronic devices.
2
2. Block Diagram
32.768 kHz
CLOCK
and
CALENDAR
OSC
DIVIDER
FOUT
FOE
FOUT
CONTROLLER
TIMER
REGISTER
/ INT
INTERRUPT
CONTROLLER
ALARM
REGISTER
SCL
SDA
I C-BUS
INTERFACE
CIRCUIT
2
CONTROL
REGISTER
and
SYSTEM
CONTROLLER
Page - 1
MQ - 372 - 01
RX - 8581 SA
/
JE
/
NB
3. Terminal description
3.1. Terminal connections
RX - 8581 SA
SOP
−
14 pin
#1
# 14
#1
RX - 8581 JE
VSOJ
−
20 pin
# 14
RX - 8581 NB
SON
−
22 pin
#1
# 14
# 11
# 10
#7
#8
No. Pin terminal No. Pin terminal
1
2
3
4
5
6
7
8
9
10
N.C.
N.C.
FOE
V
DD
FOUT
SCL
SDAT
( V
DD
)
GND
/ INT
20
19
18
17
16
15
14
13
12
11
N.C.
N.C.
N.C.
N.C.
N.C.
N.C.
N.C.
N.C.
N.C.
N.C.
# 11
(#12)
No. Pin terminal No. Pin terminal
1
2
3
4
5
6
7
N.C.
SCL
SDA
N.C.
GND
N.C.
/ INT
14
13
12
11
10
9
8
FOUT
N.C.
N.C.
V
DD
FOE
N.C.
N.C.
No. Pin terminal No. Pin terminal
1
2
3
4
5
6
7
8
9
10
11
/ INT
GND
( V
DD
)
N.C.
SDA
SCL
FOUT
V
DD
FOE
N.C.
N.C.
22
21
20
19
18
17
16
15
14
(13)
(12)
N.C.
N.C.
N.C.
N.C.
N.C.
N.C.
N.C.
N.C.
N.C.
−
−
3.2. Pin Functions
Signal
name
SCL
I/O
I
2
Function
This is the serial clock input pin for I C Bus communications.
This pin's signal is used for input and output of address, data, and ACK bits,
2
synchronized with the serial clock used for I C communications.
Since the SDA pin is an N-ch open drain pin during output, be sure to connect a suitable
pull-up resistance relative to the signal line capacity.
This is the C-MOS output pin with output control provided via the FOE pin.
When FOE = "H" (high level), this pin outputs a 32.768-kHz signal.
When output is stopped, the FOUT pin = "L" (low level).
This is an input pin used to control the output mode of the FOUT pin.
When this pin's level is high, the FOUT pin is in output mode. When it is low, output via the
FOUT pin is stopped.
This pins is used to output alarm signals, timer signals, time update signals, and other
signals. This pin is an open drain pin.
This pin is connected to a positive power supply.
Although this pin has the same potential as V
DD,
it should not be connected externally.
This pin is connected to a ground.
This pin is not connected to the internal IC.
Leave N.C. pins open or connect them to GND or V
DD
.
(Note) Note with caution that in the RX-8581NB (SON-22 pin), the N.C. pins (pins 14 to
22) are interconnected via the internal frame.
SDA
I/O
FOUT
O
FOE
I
/INT
V
DD
(V
DD
)
GND
O
−
−
−
N.C.
−
Note: Be sure to connect a bypass capacitor rated at least 0.1 µF between V
DD
and GND.
Page - 2
MQ - 372 - 01
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