ADT7467 データシートの表示（PDF） - Analog Devices
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ADT7467 Datasheet PDF : 81 Pages
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ADT7467
Configuration Register 5
Bit 0: If Bit 0 is set to 1, the ADT7467 is backward compatible
temperature-wise with the ADT7460. Measurements, TMIN
calibration circuit, fan control, etc., work in the range −127°C to
+127°C. Also, care should be taken in reprogramming the
temperature limits (TMIN, operating point, THERM limits) to
their desired twos complement value, because the power-on
default for them is at Offset 64. The extended temperature range
is −64°C to 191°C. The default is 1, which is in the −64°C to
+191°C temperature range.
Bit 1 = 0 is the high frequency (22.5 kHz) fan drive signal.
Bit 1 = 1 switches the fan drive to low frequency PWM,
programmable between 10 Hz and 100 Hz, the same as the
ADT7460. The default = 0 = HF PWM.
Bit 2 sets the direction for the GPIO: 0 = input, 1 = output.
Bit 3 sets the GPIO polarity: 0 = active low, 1 = active high.
How to Set the Functionality of Pin 9
Pin 9 on the ADT7467 has four possible functions: SMBALERT,
THERM, GPIO, and TACH4. The user chooses the required
functionality by setting Bit 0 and Bit 1 of Configuration
Register 4 at Address 0x7D.
Table 4. Pin 9 Settings
Bit 0
Bit 1
Function
00
TACH4
01
THERM
10
SMBALERT
11
GPIO
RECOMMENDED IMPLEMENTATION
Configuring the ADT7467 as in Figure 15 allows the system
designer to use the following features:
• Two PWM outputs for fan control of up to three fans (the
front and rear chassis fans are connected in parallel).
• Three TACH fan speed measurement inputs.
• VCC measured internally through Pin 3.
• CPU temperature measured using Remote 1 temperature
channel.
• Ambient temperature measured through Remote 2
temperature channel.
• Bidirectional THERM pin. This feature allows Intel
Pentium 4 PROCHOT monitoring and can function as an
overtemperature THERM output. It can alternatively be
programmed as an SMBALERT system interrupt output.
FRONT
CHASSIS
FAN
REAR
CHASSIS
FAN
AMBIENT
TEMPERATURE
ADT7467
TACH2
PWM1
TACH1
CPU FAN
PWM3
TACH3
D1+
D1–
D2+
D2–
THERM
PROCHOT
CPU
SDA
SCL
SMBALERT
GND
ICH
Figure 15. ADT7467 Configuration
Rev. 0 | Page 10 of 80
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