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Epson RX-8581JE, RX-8581NB, RX-8581SA Page, MQ372-02

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RX - 8581 SA / JE / NB

I2C-Bus Interface Real-time Clock Module

RX - 8581 SA / JE / NB

•Features built-in 32.768-kHz crystal oscillator, frequency adjusted

•Supports I2C-Bus's high speed mode (400 kHz)

•Alarm interrupt function for day, date, hour, and minute settings

•Fixed-cycle timer interrupt function

• Time update interrupt function		(Seconds, minutes)
•	32.768-kHz output with OE function	(FOE and FOUT pins)
•	Auto correction of leap years	(from 2000 to 2099)

•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 ∝ A /3 V (Typ.)

•Compact package (NB: SON− 22 pin PKG)

The I2C-Bus is a trademark of PHILIPS ELECTRONICS N.V.

1. Overview

This module is an I2C 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. Block Diagram

32.768 kHz

DIVIDER

CLOCK

OSC

and

CALENDAR

FOUT

FOUT

TIMER

FOE

CONTROLLER

REGISTER

/ INT

INTERRUPT

ALARM

CONTROLLER

REGISTER

CONTROL

SCL

I2C-BUS

REGISTER

SDA

INTERFACE

and

CIRCUIT

SYSTEM

CONTROLLER

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MQ372-02

Contents

Page In pursuit of "Saving" Technology ,Epson electronic device "Saving Epson IS energy savings •The material is subject to change without notice 7.1. DC characteristics Page MQ372-02 RX - 8581 SA RX - 8581 JE RX - 8581 NB Signal I/O Item Symbol Condition Rating Unit SCL SDA 8.1. Overview of Functions 1) Clock functions 2)Fixed-cycleinterrupt generation function 3)Time update interrupt function 4)Alarm interrupt function 5)32.768-kHzclock output Address 8.2.2. Control register (Reg F) STOP RESET 1) UIE (Update Interrupt Enable) bit When a time update interrupt event occurs, an interrupt signal is not 4) STOP bit Writing a "0" to this bit cancels stop status (restarts operations) STOP Description [Normal operation mode] 8.2.3. Flag register (Reg-E) Flag register ∗ 1) ∗ 2) 1)UF (Update Flag) bit 8.2.4. Extension register (Reg-D) WADA USEL TSEL1 ∗ 3) Page Page 8.3. Fixed-cycleTimer Interrupt Function 8.3.1. Diagram of fixed-cycletimer interrupt function TE bit TIE bit /INT output 8.3.2. Related registers for function of time update interrupts TSEL1 TSEL0 interrupts from occurring inadvertently while entering settings When the SCL pin SDA pin /INT pin 8.4.1. Time update interrupt function diagram (2)When a time update interrupt event occurs, the UF bit value becomes "1 When the UF bit value is "1" its value is retained until it is cleared to zero (4)When a time update interrupt occurs, /INT pin output is low if UIE = "1 If UIE = "0" when a timer update interrupt occurs, the /INT pin status remains 8.4.2. Related registers for time update interrupt functions 1)USEL (Update Interrupt Select) bit Selects "second update" (once per second) as the timing for generation of interrupt events Selects "minute update" (once per minute) as the timing for generation of Page 8.5.2. Related registers from occurring inadvertently while entering settings 1) WADA (Week Alarm /Day Alarm) bit WADA Sets WEEK as target of alarm function 3) AF (Alarm Flag) bit The AF bit is cleared to zero to prepare for the next status detection Alarm interrupt events are not detected Alarm interrupt events are detected 4) AIE (Alarm Interrupt Enable) bit 8.6. Reading/Writing Data via the I2C Bus Interface 8.6.3. Starting and stopping I2C bus communications 0.95 s ( Max. ) 1) START condition, repeated START condition, and STOP condition (1)START condition The SDA level changes from high to low while SCL is at high level 8.6.4.Data transfers and acknowledge responses during I2C-BUScommunications 1)Data transfers However, the transfer time must be no longer than 0.95 seconds After address Fh, incrementation goes to address 0h 2)Data acknowledge response (ACK signal) Page Page RX-8581SA (SOP - 14 pin) •External dimensions R8581 E 1234A •Recommended soldering Page (1) Static electricity (2) Noise (3)Voltage levels of input pins (4) Handling of unused pins 11.2.Notes on packaging Distributor AMERICA EPSON ELECTRONICS AMERICA, INC HEADQUARTER 150 River Oaks Parkway, San Jose, CA 95134, U.S.A