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

10

FUNCTIONAL DESCRIPTION

Serial bus interface

The SA56004X should be connected to a compatible two-wire serial

interface System Management Bus (SMBus) as a slave device

using the two device terminals SCLK and SDATA. The ALERT pin

can optionally be used with the SMBus protocol to implement the

ARA response. The controller will provide a clock signal to the

device SCLK pin and write/read data to/from the device through the

device SDATA pin. External pull-up resistors, about 10 k

Ω each, are

needed for these device pins due to open drain circuitry.

Data of 8-bit digital byte or word are used for communication

between the controller and the device using SMBus 2.0 protocols

which are described more in the ‘SMBus Interface’ section on

page 17. The operation of the device to the bus is described with

details in the following sections.

Slave address

The SA56004X has a 7-bit slave address register which is factory

programmed in OTP memory. Eight unique devices are available

with different slave addresses as defined in the ‘Ordering

information’ section in Table 1, ‘Device slave address options’. Up to

eight devices can reside on the same SMBus without conflict,

provided that their addresses are unique.

Register overview

The SA56004X contains three types of SMBus addressable registers.

These are read only (R), write only (W), and read-write (R/W).

Attempting to write to any R-only register or read data from any

W-only register will produce an invalid result. Some of the R/W

registers have separate addresses for reading and writing operations.

The registers of the SA56004X serve four purposes:

Table 2 describes the names, addresses, power-on-reset (POR),

and functions of each register. The data of the temperature-related

registers is in 2’s complement format in which the MSB is the sign

bit. The 8-bit data of other registers is in 8-bit straight format.

Table 2. Register assignments

REGISTER

NAME

COMMAND BYTE

POR

STATE

FUNCTION

BITS

ACCESSIBILITY

NAME

READ

ADDRESS

WRITE

ADDRESS

STATE

LTHB

00h

NA

0000 0000

Local Temperature HIGH Byte

8

R

RTHB

01h

NA

0000 0000

Remote Temperature HIGH Byte

8

R

SR

02h

NA

0000 0000

Status Register

8

R

CON

03h

09h

0000 0000

Configuration Register

8

R/W

CR

04h

0Ah

1000

Conversion Rate

4

R/W

LHS

05h

0Bh

0100 0110

Local HIGH Setpoint

8

R/W

LLS

06h

0Ch

0000 0000

Local LOW Setpoint

8

R/W

RHSHB

07h

0Dh

0100 0110

Remote HIGH Setpoint High Byte

8

R/W

RLSHB

08h

0Eh

0000 0000

Remote LOW Setpoint High Byte

8

R/W

One Shot

NA

0Fh

Writing register initiate a one shot conversion

0

W

RTLB

10h

NA

0000 00

Remote Temperature LOW Byte

6(MSBs)

R

RTOHB

11h

11h

0000 0000

Remote Temperature Offset High Byte

8

R/W

RTOLB

12h

12h

000

Remote Temperature Offset Low Byte

3(MSBs)

R/W

RHSLB

13h

13h

000

Remote HIGH Setpoint Low Byte

3(MSBs)

R/W

RLSLB

14h

14h

000

Remote LOW Setpoint Low Byte

3(MSBs)

R/W

RCS

19h

19h

0101 0101

Remote T_CRIT Setpoint

8

R/W

LCS

20h

20h

0101 0101

RLocal T_CRIT Setpoint

8

R/W

TH

21h

21h

0 1010

T_CRIT Hysteresis

5

R/W

LTLB

22h

NA

0000 0000

Local Temperature Low Byte

3(MSBs)

R

AM

BFh

BFh

0

Alert Mode

1

R/W

RMID

FEh

NA

1010 0001

Read Manufacturer’s ID

8

R

RDR

FFh

NA

0000 0000

Read Stepping or Die Revision

8

R