SA56004X Datasheet, PDF (5/36 Pages) NXP Semiconductors – 1 Degrees Celcious accurate, SMBus-compatible, 8-pin, remote/local digital temperature sensor with over temperature alarms

NXP Semiconductors
SA56004X
Digital temperature sensor with overtemperature alarms
7. Functional description
Refer to Figure 1 “Block diagram”.
7.1 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 kΩ 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 Section 7.10 “SMBus
interface”. The operation of the device to the bus is described with details in the following
sections.
7.2 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
Table 2 “Ordering options”. Up to eight devices can reside on the same SMBus without
conflict, provided that their addresses are unique.
7.3 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:
• Control and configuration of the SA56004X
• Status reporting
• Temperature measurement storage
• ID and manufacturer test registers
Table 4 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.
SA56004X_5
Product data sheet
Rev. 05 — 22 May 2008
© NXP B.V. 2008. All rights reserved.
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