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Acrosser AR-B1320 User Manual

Page 18

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A

A

R

R

-

-

B

B

1

1

3

3

2

2

0

0

U

U

s

s

e

e

r

r

s

s

G

G

u

u

i

i

d

d

e

e

2-10

2.10 REAL-TIME CLOCK AND NON-VOLATILE RAM

The AR-B1320 contains a real-time clock compartment that maintains the date and time in
addition to storing configuration information about the computer system. It contains 14 bytes of
clock and registers and 114 bytes of general purpose RAM. Because of the use of CMOS
technology, it consumes very little power and can be maintained for long periods of time using an
internal lithium battery.

Address

Description

00

Seconds

01

Second alarm

02

Minutes

03

Minute alarm

04

Hours

05

Hour alarm

06

Day of week

07

Date of month

08

Month

09

Year

0A

Status register A

0B

Status register B

0C

Status register C

0D

Status register D

0E

Diagnostic status byte

0F

Shutdown status byte

10

Diskette drive type byte, drive A and B

11

Fixed disk type byte, drive C

12

Fixed disk type byte, drive D

13

Reserved

14

Equipment byte

15

Low base memory byte

16

High base memory byte

17

Low expansion memory byte

18

High expansion memory byte

19-2D

Reserved

2E-2F

2-byte CMOS checksum

30

Low actual expansion memory byte

31

High actual expansion memory byte

32

Date century byte

33

Information flags (set during power on)

34-7F

Reserved for system BIOS

Table 2-5 Real-Time Clock & Non-Volatile RAM