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TMP103

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SBOS545D – FEBRUARY 2011 – REVISED DECEMBER 2018

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Register Maps (continued)

Table 3. Pointer Register Byte

P7

P6

P5

P4

P3

P2

P1

P0

0

0

0

0

0

0

Register Bits

Table 4. Pointer Addresses

P1

P0

REGISTER

0

0

Temperature Register (Read Only)

0

1

Configuration Register (Read/Write)

1

0

TLOW Register (Read/Write)

1

1

THIGH Register (Read/Write)

7.6.2 Temperature Register

The Temperature Register of the TMP103 device is configured as an eight-bit, read-only register that stores the

output of the most recent conversion. A single byte must be read to obtain data, and is described in Table 5. The

data format for temperature is summarized in Table 6. One LSB equals 1°C.

Table 5. Temperature Register

D7

D6

D5

D4

D3

D2

D1

D0

T7

T6

T5

T4

T3

T2

T1

T0

Negative numbers are represented in binary twos complement format. Following power up or reset, the

Temperature Register reads 0°C until the first conversion is complete.

(1)

The resolution for the ADC is 1°C/count, where count is equal to the digital output of the ADC.

Table 6. 8-Bit Temperature Data Format(1)

TEMPERATURE (°C)

DIGITAL OUTPUT (BINARY)

HEX

128

0111 1111

7F

127

0111 1111

7F

100

0110 0100

64

80

0101 0000

50

75

0100 1011

4B

50

0011 0010

32

25

0001 1001

19

0

0000 0000

00

–1

1111 1111

FF

–25

1110 0111

E7

–55

1100 1001

C9

For positive temperatures (for example, 50°C):

Twos complement is not performed on positive numbers. Therefore, simply convert the number to binary

code, left-justified format. Denote a positive number with MSB = 0.

Example: (50°C)/(1°C/count) = 50 = 32h = 0011 0010

For negative temperatures (for example, –25°C):

Generate the twos complement of a negative number by complementing the absolute value binary number

and adding 1. Denote a negative number with MSB = 1.

Example: (|–25°C|)/(1°C/count) = 25 = 19h = 0001 1001

Twos complement format: 1110 0110 + 1 = 1110 0111