FM3808

Rev 1.1

May 2003

Page 3 of 28

Functional Truth Table

/CE

/WE

/OE

Function

H

X

X

Standby/Precharge

!

X

X

Latch Address

L

H

L

Read

L

L

X

Write

Overview

The FM3808 integrates three complementary but

distinct functions under a common interface in a

single package. First, is the 32Kx8 FRAM memory

block (minus 16 bytes), second is the real-time

clock/calendar, and third is the system supervisor.

The functions are integrated to enhance their

individual performance, so that each provides better

capability than three similar stand-alone devices. All

functions

use

the

same

bytewide

address/data

interface and are memory mapped. Special functions,

including the clock/calendar and supervisor system,

are controlled via registers that reside in the top of the

combined

memory

map.

The

register

map

is

described below, followed by a detailed description

of each functional block.

Register Map

The top 16 FRAM address locations control the

clock/calendar, alarm, and supervisor functions. The

registers contain timekeeping data, control bits, or

information flags. A short description of each register

follows. Detailed descriptions of each function follow

the register summary.

Register Map Summary Table

Data

Address

D7

D6

D5

D4

D3

D2

D1

D0

Function

Range

7FFFh

10 years

years

Years

00-99

7FFEh

0

0

0

10 mo

months

Month

1-12

7FFDh

0

0

10 date

date

Date

1-31

7FFCh

0

0

0

0

0

day

Day

1-7

7FFBh

0

0

10 hours

hours

Hours

0-23

7FFAh

0

10 minutes

minutes

Minutes

0-59

7FF9h

0

10 seconds

seconds

Seconds

0-59

7FF8h

/OSCEN reserved

reserved

CALS

CAL3

CAL2

CAL1

CAL0

Control-NV

7FF7h

WDS

/WDW

WDT5

WDT4

WDT3

WDT2

WDT1

WDT0

Watchdog

7FF6h

WIE

AIE

PFE

ABE

H/L

P/L

reserved

reserved Interrupts

7FF5h

/Match

0

Alarm 10 date

Alarm date

Alarm Date

1-31

7FF4h

/Match

0

Alarm 10 hours

hours

Alarm Hours

0-23

7FF3h

/Match

Alarm 10 minutes

Alarm minutes

Alarm Minutes

0-59

7FF2h

/Match

Alarm 10 seconds

Alarm seconds

Alarm Seconds

0-59

7FF1h

User-NV

7FF0h

WDF

AF

PF

CF

TST

CAL

W

R

Flags/Control

Note that the shaded register bits are implemented in FRAM, therefore data at these locations is retained even

without backup power.