Figure 6. Register Pages Map

DS1925

iButton High-Capacity Temperature Logger

with 122KB Data-Log Memory

www.maximintegrated.com

Maxim Integrated │ 10

ADDR

b7

b6

b5

b4

b3

b2

b1

b0

FUNCTION

ACCESS*

0200h

LSByte Seconds

Real-Time Clock

Registers

R/W; R

0201h

. . .

0202h

. . .

0203h

MSByte Seconds

0204h

(not used)

(N/A)

R; R

0205h

(not used)

(N/A)

R; R

0206h

Low Byte

Sample Rate

R/W; R

0207h

0

0

High Byte

0208h

Low Threshold

Temp Alarms

R/W; R

0209h

High Threshold

020Ah

Reserved

(N/A)

R; R

020Bh

Reserved

(N/A)

R; R

020Ch

Low Byte

0

0

0

0

0

Latest Temp

R; R

020Dh

High Byte

020Eh

Reserved

(N/A)

R; R

020Fh

Reserved

0210h

0

0

0

0

0

0

ETHA

ETLA

Temperature Alarm

Enable

R/W; R

0211h

1

1

1

1

1

1

0

0

(N/A)

R/W; R

0212h

0

0

0

0

0

0

EHSS

EOSC

RTC Control

R/W; R

0213h

1

1

SUTA

1

(X)

TLFS

0

ETL

Mission Control

R/W; R

0214h

BOR

1

1

1

0

0

THF

TLF

Alarm Status

R; R

0215h

1

1

0

WFTA

MEMCLR

0

MIP

0

General Status

R; R

0216h

Low Byte

Mission Start Delay

Counter

R/W; R

0217h

Center Byte

0218h

High Byte

0219h

LSByte Seconds

Mission Timestamp

R/W; R

021Ah

. . .

021Bh

. . .

021Ch

MSByte Seconds

021Dh

Major Version

(N/A)

R; R

021Eh

Minor Version

(N/A)

R; R

021Fh

(No function; reads 00h)

(N/A)

R; R

0220h

Low Byte

Mission Samples

Counter

R; R

0221h

Center Byte

0222h

High Byte

0223h

Low Byte

Device Samples

Counter

R; R

0224h

Center Byte

0225h

High Byte

0226h

Configuration Code

Flavor

R; R

0227h

EPW

Password

Control

R/W; R

0228h

First Byte

Read Access

Password

W; ---

…

. . .

022Fh

Eighth Byte

0230h

First Byte

Full Access

Password

W; —

…

. . .

0237h

Eighth Byte

0238h

(No function; all these bytes read 00h)

(N/A)

R; R

…

023Fh

*The first entry in the “ACCESS” column is valid between missions. The second entry shows the applicable access type while a mission is in progress.