Epson RTC-72421 Applications Manual page 4

Real time clock module

Table of Contents

Using the RTC-72421/RTC-72423 ----------------------------------------------------------------16

1. Power-on procedure (initialization) ------------------------------------------------------------------------------------16

to W registers -----------------------------------------------------------------------------------------18

3. Write to 30-second ADJ bit ----------------------------------------------------------------------------------------------18

pin ----------------------------------------------------------------------------------------------------------19

(1) Functions -----------------------------------------------------------------------------------------------------------------19

(2) Timing ---------------------------------------------------------------------------------------------------------------------19

(3) Note-----------------------------------------------------------------------------------------------------------------------19

Power supply circuit example -----------------------------------------------------------------------19

1. Connection to multiplexed bus type ------------------------------------------------------------------------------------20

2. Connection to Z80 or compatible CPU --------------------------------------------------------------------------------20

3. Connection to 68-series MPU--------------------------------------------------------------------------------------------20

Reference data -----------------------------------------------------------------------------------------21

1. Frequency temperature characteristics (typical) --------------------------------------------------------------------21

2. Frequency voltage characteristics (typical)---------------------------------------------------------------------------21

3. Current consumption voltage characteristics (typical) -------------------------------------------------------------21

External dimensions-----------------------------------------------------------------------------------22

1. RTC-72421 -------------------------------------------------------------------------------------------------------------------22

2. RTC-72423 -------------------------------------------------------------------------------------------------------------------22

Marking layout ------------------------------------------------------------------------------------------22

Application notes ---------------------------------------------------------------------------------------23

1. Notes on handling----------------------------------------------------------------------------------------------------------23

(1) Static electricity ---------------------------------------------------------------------------------------------------------22

(2) Noise ----------------------------------------------------------------------------------------------------------------------22

(3) Voltage levels of input pins ------------------------------------------------------------------------------------------22

(4) Treatment of unused input pins-------------------------------------------------------------------------------------22

2. Notes on mounting---------------------------------------------------------------------------------------------------------23

(1) Soldering temperature conditions ----------------------------------------------------------------------------------23

(2) Mounting equipment---------------------------------------------------------------------------------------------------24

(3) Ultrasonic cleaning-----------------------------------------------------------------------------------------------------24

(4) Mounting orientation---------------------------------------------------------------------------------------------------24

(5) Leakage between pins ------------------------------------------------------------------------------------------------24

CONTENTS

Table of Contents

Rtc-72423