SE95 PHILIPS [NXP Semiconductors], SE95 Datasheet - Page 10

• Manufacturer Part Number: SE95
• Description: Ultra high accuracy digital temperature sensor and thermal WatchdogE
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
I
The SE95 can be connected to a compatible 2-wire serial interface
I
device, using two device terminals, SCL and SDA. The controller
must provide the SCL clock signal and write/read data to/from the
device through the SDA terminal. Note that if the I
pull-up resistors have not been installed as required for I
then an external pull-up resistor, about 10 k , is needed for each of
these two terminals. The bus communication protocols are
described in the data communication section.
Slave address
The SE95 slave address on the I
logic applied to the device address pins A2, A1 and A0. Each pin is
typically connected either to GND for logic 0, or to V
These pins represent the three LSB bits of the device 7-bit address.
The other four MSB bits of the address data are preset to ‘1001’ by
hard wiring inside the SE95. Table 1 shows the device’s complete
address and indicates that up to 8 devices can be connected to the
same bus without address conflict. Because the input pins, SCL,
SDA, A2–A0, are not internally biased, it is important that they
should not be left floating in any application.
Table 1. Address table
1 = HIGH, 0 = LOW
Table 2. Register table
2004 Dec 21
2
2
Register name
Conf
Temp
Tos
Thyst
ID
reserved
reserved
C-bus as a slave device under the control of a controller or master
C serial interface
MSB
Ultra high accuracy digital temperature sensor and
thermal Watchdog
1
0
Pointer value
01H
00H
03H
02H
05H
04H
06H
0
2
1
C-bus is partially defined by the
R/W
R/W
Read only
R/W
R/W
Read only
N/A
N/A
A2
2
C common
CC
POR state
00H
N/A
50 00H
4B 00H
A1H
N/A
N/A
A1
for logic 1.
2
C-bus,
LSB
A0
Description
Configuration Register.
Contains a single 8-bit data byte. To set an operating condition.
Temperature Register.
Contains two 8-bit data bytes. To store the measured Temp data.
Over-temp Shutdown threshold Register.
Contains two 8-bit data bytes. To store the over-temp shut-down Tos limit.
Default = 80 C.
Hysteresis Register.
Contains two 8-bit data bytes. To store the hysteresis Thyst limit.
B7–B0 are also used in OTP test mode to supply OTP write data.
Default = 75 C.
ID Register.
Contains a single 8-bit data byte for the manufacturer ID code.
Reserved.
Reserved.
10
Register list
The SE95 contains 7 data registers. The registers can be 1 byte or
2 bytes wide, and are defined in Table 2. The registers are accessed
by the value in the content of the pointer register during I
communication. The types of registers are: read only, read/write,
and reserved for manufacturer use. Note that when reading a
two-byte register, the host must provide enough clock pulses as
required by the I
for the device to completely return both data bytes. Otherwise the
device may hold the SDA line as LOW state, resulting in a bus hang
condition.
Register pointer
The register pointer or pointer byte is an 8-bit data byte that is
equivalent to the register command in the I
used to identify the device register to be accessed for a write or read
operation. Its values are listed as pointer values in Table 2, “Register
table”. For the device register I
byte may or may not need to be included within the command as
illustrated in the I
communication” on page 14.
The command statements of writing data to a register must always
include the pointer byte; while the command statements of reading
data from a register may or may not include it. To read a register that
is different from the one that has been recently read, the pointer byte
must be included. However, to re-read a register that has been
recently read, the pointer byte may not have to be included in the
reading.
At power-up, the pointer value is preset to ‘0’ for the Temp Register;
users can then read the temperature without specifying the pointer
byte.
2
2
C protocol (see the “Data communication” section)
C protocol figures in section “Data
2
C-bus communication, the pointer
2
C-bus definitions and is
Product data sheet
SE95
2
C-bus