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Version 1 – May 2014

6/13

16-bit ID

xxxx'xxxx’xx 00’0111

bits 5 to 0: STSC1-specific product code

bits 15 to 6: unspecified information

Table 11 Structure of the 16-bit ID. Bits 15:6 of the ID contain

unspecified information (marked as “x”), which may vary from

sensor to sensor, while bits 5:0 contain the STSC1-specific

product code.

6.8 Checksum Calculation

The 8-bit CRC checksum transmitted after each data word

is generated by a CRC algorithm with the properties

displayed in Table 12. The CRC covers the contents of the

two previously transmitted data bytes.

Property

Value

Name

CRC-8

Width

8 bits

Polynomial

Initialization

0xFF

Reflect input

False

Reflect output

False

Final XOR

0x00

Examples

CRC (0x00) = 0xAC

CRC (0xBEEF) = 0x92

Table 12 STSC1

6.9 Conversion of Signal Output

Measurement data is always transferred as 16-bit values.

These values are already linearized by the STSC1.

Temperature values can be calculated with the formula

given below.

Temperature conversion formula (result in °C):

16

T

2

S

175

45

T









temperature.

6.10 Communication Data Sequences

1

2

3

4

5

6

7

8

9

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

S

P

STSC1 measuring

1 0 0 1 0 1 0 0

0 1 1 1 1 1 0 0

1 0 1 0 0 0 1 0

Measurement command MSB

Measurement command LSB

Measurement in progress

29 30 31 32 33 34 35 36 37 38 39

40 41 42 43 44 45 46 47 48 49

S

STSC1 in idle

state

S

1 0 0 1 0 1 0 1

1 0 0 1 0 1 0 1

while meas. is in prog. (polling)

measurement cont’d

measurement

completed

29 30 31 32 33 34 35 36 37 38

S

STSC1 measuring,

SCL line pulled low

1 0 0 1 0 1 0 1

while meas. is in progress

measurement continued

50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77

P

0 1 1 0 0 1 0 0

1 0 0 0 1 0 1 1

1 1 0 0 0 1 1 1

Temperature MSB

Temperature LSB

Temperature CRC checksum

Figure 5 Communication sequence for starting a measurement and reading measurement results displaying both clock stretching options.

The numerical example corresponds to a measurement command with clock stretching enabled. The physical values of the transmitted

measurement result is 23.7 °C. Clear blocks are controlled by the microcontroller, grey blocks by the STSC1.

clock stretching

disabled

clock

stretching enabled