Datasheet

Host

Device

(1)

Device

(2)

Device

(N)

Interface Logic Interface Logic Interface Logic

RX RX RX

TX TX TX

TMP104

SBOS564A –NOVEMBER 2011– REVISED NOVEMBER 2011

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INDIVIDUAL READ AND WRITE

The host can initiate an individual read/write command to a particular TMP104 in the daisy-chain by sending the

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

• P7 = 0

• P6-P3 = the device ID

• P2-P1 = the data register pointer; see Table 3

• P0 = indicates read/write control

P0 = 0 indicates an individual write command; the host must transfer one more byte of data for the register

indicated by bits P2-P1. The TMP104 in the daisy-chain that corresponds to the device ID noted by bits P6-P3

then updates the appropriate register. P0 = 1 indicates an individual read command; as shown in Figure 10, the

TMP104 in the daisy-chain that corresponds to the device ID pointed by bits P6-P3 then breaks the bus,

transmits the data from the register pointed by bits P2-P1, and reconnects the bus.

Figure 10. TMP104 Daisy-Chain: Bus Status During Individual Read Operation of Second Device

TEMPERATURE REGISTER

The Temperature Register of the TMP104 is configured as an 8-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 4. The data

format for temperature is summarized in Table 5. One LSB equals 1°C.

Table 4. Temperature Register

D7 D6 D5 D4 D3 D2 D1 D0

T7 T6 T5 T4 T3 T2 T1 T0

Product Folder Link(s): TMP104