
W83637HF
Publication Release Date: June 25, 2003
- 28 -
Revision 1.3
6.3.3 Temperature Measurement Machine
The temperature data format is 8-bit two's-complement for sensor SYSTIN and 9-bit two's-complement
for sensor CPUTIN and VTIN. 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/Bank2 CR[50h] and the
LSB from the Bank1/Bank2 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 1
6.3.3.1 Monitor temperature from thermistor:
The W83637HF 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 6.2, the themistor is connected by a serial resistor with 10K Ohms, then connect
to VREF (Pin 101).
6.3.3.2 Monitor temperature from Pentium II
TM
/Pentium III
TM
thermal diode or bipolar
transistor2N3904
The W83637HF can alternate the thermistor to Pentium II
TM
/Pentium III
TM
thermal diode interface or
transistor 2N3904 and the circuit connection is shown as Figure 6.3. The pin of Pentium II
/Pentium
III
D- is connected to pin 111(CPUD-) and the pin D+ is connected to temperature sensor pin in the
W83637HF. 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 together to act as a thermal diode.