SA56004X Datasheet, PDF (18/36 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
LOW. Furthermore, if the Remote HIGH Setpoint High Byte (RHSHB) register is set to a
value less than +127 °C and the Alert Mask is disabled, then the ALERT output will be
pulled LOW. Note that the OPEN bit itself will not trigger an ALERT.
When the D+ pin is shorted to ground or to D−, the Remote Temperature High Byte
(RTHB) register is loaded with −128 °C (1000 0000) and the OPEN (bit 2 in the Status
register) will not be set. Since operating the SA56004X is beyond its normal limits, this
temperature reading represents this shorted fault condition. If the value in the Remote
Low Setpoint High Byte (RLSHB) register is more than −128 °C and the Alert Mask is
disabled, the ALERT output will be pulled LOW.
7.10 SMBus interface
The device can communicate over a standard two-wire serial interface System
Management Bus (SMBus) or compatible I²C-bus using SCLK and SDATA. The device
employs four standard SMBus protocols: Write Byte, Read Byte, Receive Byte, and
Send Byte. Data formats of four protocols are shown in Figure 9. The following key points
of protocol are important:
• The SMBus master initiates data transfer by establishing a START condition (S) and
terminates data transfer by generating a STOP condition (P).
• Data is sent over the serial bus in sequences of 9 clock pulses according to each 8-bit
data byte followed by 1-bit status of device acknowledgement (A).
• The 7-bit slave address is equivalent to factory-programmed address of the device.
• The command byte is equivalent to the address of the selected device register.
• The Receive Byte format is used for quicker transfer data from a device reading
register that was previously selected.
SA56004X_5
Product data sheet
Rev. 05 — 22 May 2008
© NXP B.V. 2008. All rights reserved.
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