STDS75_08 Datasheet, PDF (16/37 Pages) STMicroelectronics – Digital temperature sensor and thermal watchdog

Functional description
3
Functional description
STDS75
3.1
3.1.1
The STDS75 registers have unique pointer designations which are defined in Table 5 on
page 16. Whenever any READ/WRITE operation to the STDS75 register is desired, the user
must “point” to the device register to be accessed.
All of these user-accessible registers can be accessed via the digital serial interface at
anytime (see Serial interface on page 20), and they include:
● Command register/address pointer register
● Configuration register
● Temperature register
● Over-Limit signal temperature register (T_OS)
● Hysteresis temperature register (T_HYS)
Registers and register set formats
Command/pointer register
The most significant bits (MSBs) of the command register must always be zero. Writing a '1'
into any of these bits will cause the current operation to be terminated (see Table 4).
The command register retains pointer information between operations. Therefore, this
register only needs to be updated once for consecutive READ operations from the same
register. All bits in the command register default to '0' at power-up.
Table 4. Command/pointer register format
MSB
LSB
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
0
0
0
0
0
0
P1
P0
Pointer
Table 5. Register pointers selection summary
Pointer
Value P1
(H)
P0
Name
Description
Width Type Power-on
(Bits) (R/W) default
Comments
00
0
0
TEMP
Temperature
register
16
Read
only
N/A
To store measured
temperature data
01
0
1
CONF
Configuration
register
8
R/W
00
02
1
0
T_HYS
Hysteresis
register
16 R/W
4800 Default = 75°C
03
1
1
Over-
T_OS temperature 16 R/W
shutdown
5000
Set point for over-
temperature
Shutdown (T_OS) limit
default = 80°C
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