A global read command is indicated by C[0] = 1. As shown in Figure 7-13, the TMP144 with the device ID of

0000 then breaks the bus connection, transmits the data from the register indicated by bits C[2:1] (corresponding

to data register pointer P[1:0]), and then reconnects the bus. The TMP144 with the device ID of 0001 then

repeats the same sequence, followed by the rest of the TMP144 devices in the daisy-chain.

GLBL

IN3/ID3

IN2/ID2

IN1/ID1

IN0/ID0

P1

P0

R/W

0

1

1

1

1

1

P0

P1

S

P

0

1

0

1

0

1

0

1

S

P

Calibration Byte (55h)

Command Byte

D11

D12

D13

D14

D15

D8

D9

D10

S

P

D3

D4

D5

D6

D7

D0

D1

D2

S

P

Device-1 Data Byte-1

Device-1 Data Byte-2

Host TX

Host RX

Host TX

Host RX

D11

D12

D13

D14

D15

D8

D9

D10

S

P

D3

D4

D5

D6

D7

D0

D1

D2

S

P

Device-2 Data Byte-1

Device-2 Data Byte-2

Host TX

Host RX

0

1

1

1

1

1

P0

P1

S

P

0

1

0

1

0

1

0

1

S

P

Devices

in Pass

Through

Figure 7-13. Global Read Command Flow

Table 7-3. Pointer Addresses

P1

P0

REGISTER

0

0

Temperature register (read-only)

0

1

Configuration register (read/write)

1

0

1

1

7.5.6 Individual Read and Write

The host can initiate an individual read and write command to a particular TMP144 device in the daisy-chain by

sending the read/write command. The read/write command consists of these parameters:

• C[7] = 0 (Individual device access)

• C[6:3] = the device ID (ID[3:0])

• C[2:1] = the data register pointer (P[1:0]); see Table 7-3

• C[0] = indicates read/write control

As shown in Figure 7-14, an individual device write command is indicated by C[0] = 0. The host must transfer at

least one more byte of data for the register indicated by bits C[2:1]. The TMP144 in the daisy-chain that

corresponds to the device ID noted by bits C[6:3] then updates the appropriate register.

GLBL

IN3/ID3

IN2/ID2

IN1/ID1

IN0/ID0

P1

P0

R/W

ID0

ID1

ID2

ID3

0

0

P0

P1

S

P

0

1

0

1

0

1

0

1

S

P

Calibration Byte (55h)

Command Byte

D11

D12

D13

D14

D15

D8

D9

D10

S

P

D3

D4

D5

D6

D7

D0

D1

D2

S

P

Host Data Byte-1

Host Data Byte-2

Figure 7-14. Individual Write Command Flow

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TMP144

SBOS891A – OCTOBER 2018 – REVISED FEBRUARY 2021

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