Philips Semiconductors

Product data sheet

SA56004X

±1 °C accurate, SMBus-compatible, 8-pin, remote/local

digital temperature sensor with over temperature alarms

2004 Oct 06

12

SA56004 SMBus REGISTERS

Command Register

The command register selects which register will be read or written

to. Data for this register should be transmitted during the Command

Byte of the SMBus write communication.

Local and Remote Temperature registers

(LTHB, LTLB, RTHB, RTLB)

Table 4. Local and Remote Temperature registers

bit assignment

High Byte (Read only address 00h, 01h)

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Value

Sign

64

32

16

8

4

2

1

Low Byte (Read only address 10h)

Bit

D7

D6

D5

D4

D3

D2

D1

D0

Value

0.5

0.25

0.125

0

0

0

0

0

Configuration register

The configuration register is an 8-bit register with read address 03h

and write address 09h. Table 5 shows how the bits in this register

are used.

Table 5. Configuration Register (CON)

bit assignments

Bit

Name/Function

POR

state

7

(MSB)

ALERT mask

The ALERT interrupt is enabled when this bit is

LOW. The ALERT interrupt is disabled

(masked) when this bit is HIGH.

0

6

RUN/STOP

Standby or run mode control: Running mode is

enabled when this bit is LOW. The SA56004X

is in standby mode when this bit is HIGH.

0

5

Not defined. Defaults to “0” (zero).

0

4

Remote T_CRIT mask

The T_CRIT output will be activated by a

remote temperature that exceeds the remote

T_CRIT setpoint when this bit is LOW. The

T_CRIT output will not be activated under this

condition when this bit is HIGH.

0

3

Not defined. Defaults to “0” (zero).

0

2

Local T_CRIT mask

The T_CRIT output will be activated by a local

temperature that exceeds the local T_CRIT

setpoint when this bit is LOW. The T_CRIT

output will not be activated under this condition

when this bit is HIGH.

0

1

Not defined. Defaults to “0” (zero).

0

0

Fault Queue

A single remote temperature measurement

outside the HIGH, LOW or T_CRIT setpoints

will trigger an outside limit condition resulting in

setting the status bits and associated output

pins when this bit is LOW. Three consecutive

measurements outside of one of these

setpoints are required to trigger an outside of

limit condition when this bit is HIGH.

0

Status register

The contents of the status register reflects condition status resulting

from all activities: comparison between temperature measurements

and temperature limits, the status of A/D conversion, and the

hardware condition of external diode to the device. Bit assignments

are listed in Table 6. This register is read only and its address is 02h.

Upon POR, all bits are set to zero.

Note: any one of the fault conditions, with the exceptions of Diode

OPEN and A/D BUSY, introduces an Alert interrupt (see Alert

interrupt section on page 14). Also, whenever a one-shot command

is executed, the status byte should be read after the conversion is

completed, which is about 38 ms (1 conversion time period) after the

one-shot command is sent.