Instruction/ maintenance manual of the product RTC-72423 Epson
Go to page of 25
M Q 162-0 3 Application Manua l Real Time Clock Module RTC-72421/72423 Model Product Number R T C - 72421 A Q4272421 x 000100 R T C - 72421 B Q4272421 x 000200 R T C - 72423 A Q4272423 x 000600 R T C .
N O T I C E • 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.
RTC - 72421 / 72423 CONTENTS Ov ervi ew ............................................................................................. 1 Block diagram ..................................................................................... 1 Term inal connections .
RTC - 72421 / 72423 Page - 1 MQ - 162 - 03 4-BIT PARALLEL INTERFACE REAL TIME CLOCK MODULE RTC - 72421 / 72423 • Built-in crystal unit removes need for adjustment and reduces installation costs • M icroprocessor bus compatible ( tW W, t RD = 120 ns ) • Use of C-M OS IC enables low current consumption ( 5 µ A Max .
RTC - 72421 / 72423 Page - 2 MQ - 162 - 03 Terminal connections RTC-72421 RTC-72423 1 2 3 4 5 6 7 8 9 18 17 16 15 14 13 12 10 11 STD.P CS 0 ALE A 0 A 1 A 2 A 3 RD GND V DD () V DD ( V DD ) CS 1 D 0 1 2 3 WR D D D 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 13 14 STD.
RTC - 72421 / 72423 Page - 3 MQ - 162 - 03 Terminal functions Pin No. Signal RTC-72421 RTC-72423 Input/o u tput Function D 0 -D 3 (Data bus) 11 − 14 14 − 16, 19 Bi- directi on Connect these pines to a bi-directional data bus or CP U data bus. Use this bus to read to and write from the internal counter and registers.
RTC - 72421 / 72423 Page - 4 MQ - 162 - 03 Characteristics 1. Abso lute ma ximu m ratings Item Sy mbol Condition Specificat ion Unit Supply volt age V DD Ta=+25 ° C − 0.3 to 7.0 V Input volt age V I Ta=+25 ° C GND − 0.3 t o V DD +0.3 V Output volt age V O Ta=+25 ° C GND − 0.
RTC - 72421 / 72423 Page - 5 MQ - 162 - 03 Switching characteristics (AC characteristics) 1. W hen ALE is used W rite mode ( V DD =5 V ± 0.5 V, RTC-72421;Ta= − 10 ° C to +70 ° C, RTC-72423;Ta= − 40 ° C to +85 ° C ) Item Symbol Condition Min.
RTC - 72421 / 72423 Page - 6 MQ - 162 - 03 2. W hen ALE is f ix ed at V DD W rite mode ( V DD =5 V ± 0.5 V, RTC-72421;Ta= − 10 ° C to +70 ° C, RTC-72423;Ta= − 40 ° C to +85 ° C ) Item Symbol Condition Min.
RTC - 72421 / 72423 Page - 7 MQ - 162 - 03 Registers 1. Register table Data Address (Hex) A3 A2 A1 A0 Register name D3 D2 D1 D0 Count (BCD) Remarks 0 0 0 0 0 S1 s8 s4 s2 s1 0 to 9 1-second di g it.
RTC - 72421 / 72423 Page - 8 MQ - 162 - 03 4. Setting the fixed-period pulse output m ode and f ixed-period interrupt m ode Mode MASK ITRPT/ST ND ITRPT/STND STD.
RTC - 72421 / 72423 Page - 9 MQ - 162 - 03 Register description 1. Timing r eg isters (1) S1 to Y10 regi s ters These regist ers are 4-bit, posi tive logic regist ers in which the digits of the year, m onth, day, hour, m inute, and s econd are continuous ly w ritten i n B CD code.
RTC - 72421 / 72423 Page - 10 MQ - 162 - 03 2. CD reg ist er (control reg ist er D) (1) HOLD bit (D0) Use the HOLD bit when acc essing the S1 and W regist ers. For details , see "Read/write of S1 t o W regis t ers ". HOLD bit Function HOLD bit 0 The BUSY bit i s alway s 1 (the BU SY status cannot be checked).
RTC - 72421 / 72423 Page - 11 MQ - 162 - 03 IRQ FL AG bit *STD . P pin output 01 0 1 Inte rrupt ge ne ratio n (in sy nchron izati o n wi th co u nt i ncre m e nta ti o n) W riting o f 0 IRQ FLAG b it. The output level s of the STD.P pi n are low (down) and open circuit (up).
RTC - 72421 / 72423 Page - 12 MQ - 162 - 03 2.Fixed-period interrupt m ode (ITRPT/STND=1) 1 1 1 0 0 0 0 Nothing is output bec ause the MASK bit is at 1 Interrupt tim ing Reset at the poi nt at which 0 i s wri tten to the I RF FLAG bit No int errupts ar e generated whil e the M ASK bit is at 1 *STD .
RTC - 72421 / 72423 Page - 13 MQ - 162 - 03 4. CF reg ister (control reg ister F) (1) RESET bi t (D0) W riting 1 to the RESET bit clears the s ub-second bits of t he internal counter down to the 1/256-seconds counter. The reset continues f or as long as the RESET bit is 1.
RTC - 72421 / 72423 Page - 14 MQ - 162 - 03 Using the RTC-72421/RTC-72423 1. Power-on procedure ( init ialization) W hen pow er is turned on, the contents of all regis ters and the output from the S TD.P pin are undefined. Therefore, all the regi ster s mus t be initialized aft er power on.
RTC - 72421 / 72423 Page - 15 MQ - 162 - 03 (A)Starting the count START Set the C F regis ter Reg.F T EST 24/12 ST OP RESET Reg.D 30 s ADJ IR Q F LA G HOLD To nex t pr ocess 0 0 0 0 or 1 0*00B T his s etting is not necessar y when the ST D.
RTC - 72421 / 72423 Page - 16 MQ - 162 - 03 2. Read/write of S1 to W register s Use one of t he procedures shown below to access registers other t han the control regis ters (CD, CE, and CF) while the RTC is operating. Not e t hat the control regi s ters can be acc es sed regardless of t he status of t he BUSY bit.
RTC - 72421 / 72423 Page - 17 MQ - 162 - 03 4. Using t he CS 1 pin The RTC-72421/RTC-72423 has 2 c hip-select si gnal system s: CS 0 and CS1. Us e CS 0 as chip-sel ect for ordinary bus acces s. CS 1 is not onl y us ed for CPU bus cont rol , it also has t he m ain funct i on of s w itchi ng bet w een standby m ode and operating mode.
RTC - 72421 / 72423 Page - 18 MQ - 162 - 03 Examples of connection to general-purpose microprocessor W hen connecting t he RTC-72421/RTC-72423 to a mic roprocessor, caref ully check t he AC timings of both the RTC and the mic roprocessor.
RTC - 72421 / 72423 Page - 19 MQ - 162 - 03 External dimensions 1. RTC-72421 23.1 Max. 6.3 4.2 Max. 2.54 Min. 0.2 Min. 2.54 0.46 7.62 0 - 15 0.25 1.
RTC - 72421 / 72423 Page - 20 MQ - 162 - 03 Reference data [Finding the frequenc y s t ability] 1. Frequency and t em perature charact eri s tics can be approxim ated using the f ol l owing equati ons .
RTC - 72421 / 72423 Page - 21 MQ - 162 - 03 Application notes 1. Notes on handling This module uses a C -MO S IC to realize low power consumption. Carefully note the follow ing cautions when handling.
Application Manual AME RIC A EPSON ELECTRONICS AMERICA , INC. HEA DQUA RTER 150 River Oaks Parkw ay , San Jose, CA 95134, U.S.A. Phone: (1)800-228-3964 (Toll free) : (1)408-922-0200 (Main) Fax: (1)408-922-0238 htt p://www. eea.epson.com A tl anta Office 3010 Roy al Blvd.
An important point after buying a device Epson RTC-72423 (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought Epson RTC-72423 yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Epson RTC-72423 - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Epson RTC-72423 you will learn all the available features of the product, as well as information on its operation. The information that you get Epson RTC-72423 will certainly help you make a decision on the purchase.
If you already are a holder of Epson RTC-72423, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime Epson RTC-72423.
However, one of the most important roles played by the user manual is to help in solving problems with Epson RTC-72423. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Epson RTC-72423 along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
