Philips Semiconductors

Product data sheet

SE95

Ultra high accuracy digital temperature sensor and

thermal Watchdog

™

2004 Dec 21

11

Configuration register

The Configuration register is a write/read register and contains an 8-bit non-complement data byte that is used to configure the device for

different operating conditions. The Configuration register table (Table 3) shows the bit assignments of this register.

Table 3. Configuration register table

Bit

Name

R/W

POR

Description

B7

Reserved

R/W

0

Reserved for manufacturer’s use.

B6–B5

Rate val

R/W

00

Sets the conversion rate:

00 = 10 conversions/sec (default)

01 = 0.125 conversions/sec

10 = 1 conversions/sec

11 = 30 conversions/sec

B4–B3

OS Fault queue

R/W

0

For OS Fault Queue programming.

Programmable queue data = 0, 1 ,2, 3 for queue value = 1, 2, 4, 6 respectively. Default = 0.

B2

OS Polarity

R/W

0

For OS Polarity selection.

1 = OS active HIGH, 0 = OS active LOW (default).

B1

OS Comp/Interrupt

R/W

0

For OS operation Mode selection.

1 = OS interrupt, 0 = OS comparator (default).

B0

Shut-down

R/W

0

For Device Operation Mode selection.

1 = Shut-down, 0 = Normal (default).

Temperature Register (Temp)

The Temp register holds the digital result of temperature measurement or monitor at the end each A-to-D conversion. This register is read only

and contains two 8-bit data bytes consisting of one most significant (MS) data byte and one least significant (LS) data byte. However, only 13

bits of those two bytes are used to store the Temp data in 2’s complement format with the resolution of 0.03125

°C. The Temp register table

(Table 4) shows the bit arrangement of the Temp data in the data bytes.

Table 4. Temp Register table

Temp MS byte

Temp LS byte

MSB

LSB

MSB

LSB

B7

B6

B5

B4

B3

B2

B1

B0

B7

B6

B5

B4

B3

B2

B1

B0

for 11-bit Temp Data

Not used

MSB

LSB

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

X

X

X

X

X

for 13-bit Temp Data

Not used

MSB

LSB

D12

D11

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

X

X

X

When reading the Temp register, all 16 bits of the two data bytes (MS byte and LS byte) must be collected and then the 2’s complement data

value according to the desired resolution must be selected for the temperature calculation. The Table 4 has shown the examples for two cases:

11-bit 2’s complement data value, and 13-bit 2’s complement data value. When converting into the temperature the proper resolution must be

used as listed in Table 5 using either one of these two formulae:

1. If the Temp Data MSB = 0, then:

Temp Value (

°C) = +(Temp Data) × Value Resolution

2. If the Temp Data MSB = 1, then:

Temp Value (

°C) = –(2’s complement Temp Data) × Value Resolution

Table 6 shows some examples of the results for the 11-bit calculations.

Table 5. Temp Data and Temp Value resolution

Data resolution

Value resolution

8 bits

1.0

°C

9 bits

0.5

°C

10 bits

0.25

°C

11 bits

0.125

°C

12 bits

0.0625

°C

13 bits

0.03125

°C