
W83697HF/F
Publication Release Date: Feb. 2002
- 87 - Revision 0.70
9.3.3
Temperature Measurement Machine
The temperature data format is 8-bit two's-complement for sensor 1 and 9-bit two's-complement for
sensor 2. The 8-bit temperature data can be obtained by reading the CR[27h]. The 9-bit temperature data
can be obtained by reading the 8 MSBs from the Bank1 CR[50h] and the LSB from the Bank1 CR[51h]
bit 7. The format of the temperature data is show in Table 1.
Temperature
8-Bit Digital Output
9-Bit Digital Output
8-Bit Binary
8-Bit Hex
9-Bit Binary
9-Bit Hex
+125
°
C
0111,1101
7Dh
0,1111,1010
0FAh
+25
°
C
0001,1001
19h
0,0011,0010
032h
+1
°
C
0000,0001
01h
0,0000,0010
002h
+0.5
°
C
-
-
0,0000,0001
001h
+0
°
C
0000,0000
00h
0,0000,0000
000h
-0.5
°
C
-
-
1,1111,1111
1FFh
-1
°
C
1111,1111
FFh
1,1111,1110
1FFh
-25
°
C
1110,0111
E7h
1,1100,1110
1CEh
-55
°
C
1100,1001
C9h
1,1001,0010
192h
Table 2.
9.3.3.1 Monitor temperature from thermistor:
The W83697HF can connect three thermistors to measure three different envirment temperature. The
specification of thermistor should be considered to (1)
β
value is 3435K, (2) resistor value is 10K ohms at
25
°
C. In the Figure 9.2, the themistor is connected by a serial resistor with 10K Ohms, then connect to
VREF (Pin 101).
9.3.3.2 Monitor temperature from Pentium II
TM
thermal diode or bipolar transistor 2N3904
The W83697HF can alternate the thermistor to Pentium II
TM
(Deschutes) thermal diode interface or
transistor 2N3904 and the circuit connection is shown as Figure 9.3. The pin of Pentium II
TM
D- is
connected to power supply ground (GND) and the pin D+ is connected to pin VTINx in the W83697HF.
The resistor R=30K ohms should be connected to VREF to supply the diode bias current and the
bypass capacitor C=3300pF should be added to filter the high frequency noise. The transistor 2N3904
should be connected to a form with a diode, that is, the Base (B) and Collector (C) in the 2N3904 should
be tied togeter to act as a thermal diode.