STDS75DS2E STMICROELECTRONICS [STMicroelectronics], STDS75DS2E Datasheet - Page 18

• Manufacturer Part Number: STDS75DS2E
• Description: Digital temperature sensor and thermal watchdog
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

3.1.3
Note:
3.1.4
18/37
Temperature register
The Temperature register is a two-byte (16-bit) “Read only” register (see
page
two’s complement format, and the contents of this register are updated each time the A/D
conversion is finished.
The user can read data from the Temperature Register at any time. When a A/D conversion
is completed, the new data is loaded into a comparator buffer to evaluate fault conditions,
and will update the Temperature Register if a read cycle is not ongoing. The STDS75 is
continuously evaluating fault conditions regardless of READ or WRITE activity on the bus. If
a READ is ongoing, the previous temperature will be read. The readable temperature will be
updated upon the completion of the next A/D conversion that is not masked by a read cycle.
Depending on the A/D conversion resolution, the 9-, 10-, 11- or 12-bit MSBs of the register
will contain temperature data. All unused bits following the digital temperature will be zero.
The MSB (Bit 15) of the Temperature Register denotes whether the temperature data is
positive or negative. A '0' in Bit 15 is positive and a '1' is negative.
Table 8.
These are comparable formats to the DS75 and LM75.
Over-limit temperature register (T
The T
programmable upper trip-point temperature for the thermal alarm in two’s complement
format (see
0000 0000).
The format of the T
of the T
ignored. The MSB position contains the sign bit for the digital temperature and Bit14
contains the temperature MSB.
The resolution setting for the A/D conversion determines how many bits of the T
are used by the thermal alarm. For example, for 9-bit conversions, the trip-point temperature
is defined by the 9 MSBs of the T
Keys:
STDS75
Bytes
Bits
18). Digital temperatures from the ADC are stored in the Temperature Register in
OS
TMSB =Temperature MSB
TLSB =Temperature LSB
OS
Register is a two-byte (16-bit) READ/WRITE register that stores the user-
SB =Two’s complement Sign Bit
TD =Temperature Data
MSB
Register are hardwired to zero, so data written to these register bits will be
SB
15
Table 9 on page
Temperature register format
TMSB TD TD TD TD TD TD
14
OS
Register is identical to that of the Temperature Register. The 4 LSBs
13
MS Byte
12
19). This register defaults to 80°C at power-up (i.e., 0101 0000
THSB
OS
11
register, and all remaining bits are “Don’t cares.”
10
9
OS
)
8
9-bit
LSB
7
10-bit
LSB
6
11-bit
LSB
TLSB
5
LS Byte
12-bit
LSB
4
Table 8 on
3 2 1
0 0 0
OS
Register
LSB
0
0