Table 7-2. Command Byte Value (continued)

COMMAND

OPERATION

COMMAND BYTE ENCODING

HEX VALUE

C7 (MSB)

C6

C5

C4

C3

C2

C1

C0 (LSB)

GLBL

IN3/ID3

IN2/ID2

IN1/ID1

IN0/ID0

P1

P0

R/W

Global address

assignment

1

0

0

1

0

0

0

0

90

Global clear

interrupt

1

0

1

0

1

0

0

1

A9

Global write

1

1

1

1

0

P1

P0

0

Based on P[1:0]

Global read

1

1

1

1

0

P1

P0

1

Based on P[1:0]

Individual write

0

ID3

ID2

ID1

ID0

P1

P0

0

Based on ID[3:0] and

P[1:0]

Individual read

0

ID3

ID2

ID1

ID0

P1

P0

1

Based on ID[3:0] and

P[1:0]

7.5.2 Global Software Reset

The host can initiate a global software reset command (C[7:0] = 10110100) to all TMP144 devices in the daisy-

chain as shown in Figure 7-6. Upon receiving this command, the TMP144 resets all of its internal registers

except for the device ID and reconnects the bus. If the bus is broken before the initiation of this command, all

TMP144 devices before the broken bus point receive the command. If the host intends to initiate a global

software reset across all TMP144 devices in the chain, this command must be transmitted multiple times until it

echoes back to the host.

GLBL

IN3/ID3

IN2/ID2

IN1/ID1

IN0/ID0

P1

P0

R/W

0

1

1

0

1

0

0

1

S

P

0

1

0

1

0

1

0

1

S

P

Calibration Byte (55h)

Command Byte

Figure 7-6. Global Software Reset Command Flow

7.5.3 Global Initialization and Address Assignment Sequence

At device power-up, every TMP144 in the daisy-chain is connected in transparent mode, as shown in Figure 7-7.

Interface Logic

RX

TX

Interface Logic

RX

TX

Interface Logic

RX

TX

Host

RX

TX

Figure 7-7. TMP144 Daisy-Chain: Bus Status at Start of Global Initialization

TMP144

SBOS891A – OCTOBER 2018 – REVISED FEBRUARY 2021

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