1°C Triple SMBus Temperature Sensor

Datasheet

Revision 2.3 (04-19-05)

10

SMSC EMCT03

DATASHEET

3.5

Legacy Temperature Data Format Registers 00h, 23h, 01h,

10h, F8h, F9h:

For registers displaying legacy temperature data format, the temperature range spans from –63.875ºC

to +127.875ºC with 0,125ºC resolution. Temperatures outside this range are clipped to –63.875ºC and

+127.875ºC. Data is stored in the registers in 2’s complement as shown in Table 3.7:

3.6

Extended Temperature Data Format Registers FAh, FBh, FCh,

FDh

For registers displaying extended temperature data format, a value of 64d is subtracted from the

Legacy Format output. This effectively extends the range to cover higher external temperature

measurements while still maintaining the 2’s complement format. Obviously, the host will have to

compensate and add 64d to the read temperature data. This format spans from –63.875ºC to

+191.875ºC with 0.125ºC resolution. Temperatures outside this range are limited to –63.875ºC and

+191.875ºC. Table 3.8 shows example temperature readings and register content for this data format.

Table 3.7 Legacy Temperature Data Format

TEMPERATURE (

°C)

2’S COMPLEMENT

HEX

Diode Fault

1000 0000 0000 0000

8000

= -63.875

1100 0000 0010 0000

C020

-63

1100 0001 0000 0000

C100

-1

1111 1111 0000 0000

FF00

0

0000 0000 0000 0000

0000

+0.125

0000 0000 0010 0000

0020

+1

0000 0001 0000 0000

0100

+127

0111 1111 0000 0000

7F00

≥ +127.875

0111 1111 1110 0000

7FE0

Table 3.8 Extended Temperature Data Format

ACTUAL TEMP.

(

°C)

-64

°C OFFSET

(

°C)

2’S COMPLEMENT

OF -64

°C OFFSET

HEX

Diode Fault

1000 0000 0000 0000

8000

= -63.875

-127.875

1000 0000 0010 0000

8020

-63

-127

1000 0001 0000 0000

8100

-1

-65

1011 1111 0000 0000

BF00

0

-64

1100 0000 0000 0000

C000

+0.125

-63.875

1100 0000 0010 0000

C020

+1

-63

1100 0001 0000 0000

C100

+63

-1

1111 1111 0000 0000

FF00

+64

0

0000 0000 0000 0000

0000