Epson RTC-72421 A - Manual (Page 3)

RTC - 72421 / 72423
CONTENTS
„ Overview ............................................................................................. 1
„ Block diagram ..................................................................................... 1
„ Terminal connections .......................................................................... 2
„ Terminal functions............................................................................... 3
„ Characteristics .................................................................................... 4
1. Absolute maximum ratings........................................................................................ 4
2. Recommended operating conditions ......................................................................... 4
3. Frequency characteristics and current consumption characteristics.......................... 4
4. Electrical characteristics ( DC characteristics ) ......................................................... 4
„ Switching characteristics
(AC characteristics)
........................................... 5
1. When ALE is used .................................................................................................... 5
2. When ALE is fixed at V DD ......................................................................................... 6
„ Registers............................................................................................. 7
1. Register table............................................................................................................ 7
2. Notes ........................................................................................................................ 7
3. Functions of register bits (overview).......................................................................... 7
4. Setting the fixed-period pulse output mode and fixed-period interrupt mode............. 8
5. Resetting the fixed-period pulse output mode and fixed-period interrupt mode......... 8
„ Register description ............................................................................ 9
1. Timing registers ........................................................................................................ 9
2. CD register (control register D) ............................................................................... 10
3. CE register (control register E)................................................................................ 11
4. CF register (control register F) ................................................................................ 13
„ Using the RTC-72421/RTC-72423 .....................................................14
1. Power-on procedure (initialization) .......................................................................... 14
2. Read/write of S1 to W registers .............................................................................. 16
3. Write to 30-second ADJ bit ..................................................................................... 16
4. Using the CS 1 pin ................................................................................................... 17
„ Power supply circuit example.............................................................17
„ Examples of connection to general-purpose microprocessor .............18
„ External dimensions...........................................................................19
„ Marking layout....................................................................................19
„ Reference data ..................................................................................20
„ Application notes................................................................................21
1. Notes on handling ................................................................................................... 21
2. Notes on packaging ................................................................................................ 21