TMP122, TMP124

7

SBOS272B

www.ti.com

READ ADDRESS REGISTER

Figure 7 shows the internal register structure of the

TMP122/TMP124. Table III describes the addresses of the

registers available. The READ address register uses the two

bits to identify which of the data registers should respond to

a read command. Following a complete 16-bit read, the

READ address register is reset to the default power-up state

of P1/P0 equal 0/0.

The user can obtain 9, 10, 11, or 12 bits of resolution by

addressing the Configuration Register and setting the reso-

lution bits accordingly. For 9-, 10-, or 11-bit resolution, the most

significant bits in the Temperature Register are used with the

unused LSBs set to zero.

CONFIGURATION REGISTER

The Configuration Register is a 16-bit read/write register

used to store bits that control the operational modes of the

temperature sensor. Read/write operations are performed

MSB first. The format of the Configuration Register for the

TMP122/TMP124 is shown in Table VI, followed by a break-

down of the register bits. The power-up/reset value of the

Configuration Register bits R1/R0 equal 1/1, all other bits

equal zero.

TEMPERATURE

(

(BINARY)

HEX

150

0100 1011 0000 0111

4B07

125

0011 1110 1000 0111

3E87

25

0000 1100 1000 0111

0C87

0.0625

0000 0000 0000 1111

000F

0

0000 0000 0000 0111

0007

–0.0625

1111 1111 1111 1111

FFFF

–25

1111 0011 1000 0111

F387

–55

1110 0100 1000 0111

E487

NOTE: (1) The last 2 bits are high impedance and are shown as 11 in the table.

TABLE V. Temperature Data Format.

TEMPERATURE REGISTER

The Temperature Register of the TMP122/TMP124 is a 16-

bit, signed read-only register that stores the output of the

most recent conversion. The TMP122/TMP124 are speci-

fied for the temperature range of –40

°C to +125°C with

operation from –55

°C to +150°C. Up to 16 bits can be read

to obtain data and are described in Table IV. The first 13 bits

are used to indicate temperature where bit D2 is 1, and D1,

D0 are in a high impedance state. Data format for tempera-

ture is summarized in Table V. Following power-up or reset,

the Temperature Register will read 0

°C until the first conver-

sion is complete.

SHUTDOWN MODE (SD)

The Shutdown Mode of the TMP122/TMP124 can be used to

shut down all device circuitry except the serial interface.

Shutdown mode occurs when the last 8 bits of the WRITE

command are equal to 1, and will occur once the current

conversion is completed, reducing current consumption to

less than 1

µA. To take the part out of shutdown, send any

command or pattern after the 16-bit read with the last 8 bits

not equal to one. Power on default is in active mode.

P1

P0

REGISTER

0

0

Temperature Register (READ Only)

0

1

Configuration Register (READ/WRITE)

10

11

TABLE III. Pointer Addresses of the TMP122 and TMP124

Registers.

FIGURE 7. Internal Register Structure of the TMP122 and

TMP124.

D15

D14

D13

D12

D11

D10

D9

D8

0

0

0

0

D1

D0

R1

R0

D7

D6

D5

D4

D3

D2

D1

D0

F1

F0

POL

TM1

TM0

0

1

0

TABLE VI. Configuration Register.

I/O

Control

Interface

SCK

SO/I

Temperature

Register

Configuration

Register

T

LOW

Register

T

HIGH

Register

READ Address

Register

CS

D15

D14

D13

D12

D11

D10

D9

D8

T12

T11

T10

T9

T8

T7

T6

T5

D7

D6

D5

D4

D3

D2

D1

D0

T4

T3

T2

T1

T0

1

Z

Z

TABLE IV. Temperature Register.