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Table 4. PIN ASSIGNMENT
Pin No.
Mnemonic
1
2
3
4
5
GPIO0
6
GPIO1
7
GPIO2
8
GPIO3
9
TACH3
10
PWM2/
SMBALERT
11
TACH1
12
TACH2
13
PWM3
ADDREN
14
TACH4/
THERM/
SMBALERT/
GPIO6/
ADDR SELECT
15
16
17
18
19
GPIO4
20
+5.0 V
21
+12 V
22
+2.5 V
THERM
23
24
PWM1/
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SDA
Digital I/O (Open Drain). SMBus bidirectional serial data. Requires SMBus pullup.
SCL
Digital Input (Open Drain). SMBus serial clock input. Requires SMBus pullup.
GND
Ground Pin.
V
Power Supply. Powered by 3.3 V standby, if monitoring in low power states is required. V
CC
monitored through this pin.
VID0/
Digital Input. Voltage supply readouts from CPU. This value is read into the VID/GPIO register (0x43).
General-Purpose Open Drain Digital I/O.
VID1/
Digital Input. Voltage supply readouts from CPU. This value is read into the VID/GPIO register (0x43).
General-Purpose Open Drain Digital I/O.
VID2/
Digital Input. Voltage supply readouts from CPU. This value is read into the VID/GPIO register (0x43).
General-Purpose Open Drain Digital I/O.
VID3/
Digital Input. Voltage supply readouts from CPU. This value is read into the VID/GPIO register (0x43).
General-Purpose Open Drain Digital I/O.
Digital Input (Open Drain). Fan tachometer input to measure speed of Fan 3.
Digital Output (Open Drain). Requires 10 kW typical pullup. Pulse width modulated output to control Fan
2 speed. Can be configured as a high or low frequency drive.
Digital Output (Open Drain). This pin can be reconfigured as an SMBALERT interrupt output to signal
out-of-limit conditions.
Digital Input (Open Drain). Fan tachometer input to measure speed of Fan 1.
Digital Input (Open Drain). Fan tachometer input to measure speed of Fan 2.
Digital I/O (Open Drain). Pulse width modulated output to control the speed of Fan 3 and Fan 4.
Requires 10 kW typical pullup. Can be configured as a high or low frequency drive.
If pulled low on powerup, the ADT7476A enters address select mode, and the state of Pin 14 (ADDR
SELECT) determines the ADT7476A's slave address.
Digital Input (Open Drain). Fan tachometer input to measure speed of Fan 4.
Alternatively, the pin can be reconfigured as a bidirectional THERM pin. Times and monitors assertions
on the THERM input. For example, it can be connected to the PROCHOT output of Intel's Pentium
processor or to the output of a trip point temperature sensor. Can be used as an output to signal
overtemperature conditions.
Digital Output (Open Drain). This pin can be reconfigured as an SMBALERT interrupt output to signal
out-of-limit conditions.
General-Purpose Open Drain Digital I/O.
If in address select mode, the logic state of this pin defines the SMBus device address.
D2–
Cathode Connection to Second Thermal Diode.
D2+
Anode Connection to Second Thermal Diode.
D1–
Cathode Connection to First Thermal Diode.
D1+
Anode Connection to First Thermal Diode.
VID4/
Digital Input. Voltage supply readouts from CPU. This value is read into the VID/GPIO register (0x43).
General-Purpose Open Drain Digital I/O.
Analog Input. Monitors 5.0 V power supply.
IN
/
Analog Input. Monitors 12 V power supply.
IN
VID5
Digital Input. Voltage supply readouts from CPU. This value is read into the VID/GPIO register (0x43).
/
Analog Input. Monitors 2.5 V supply, typically a chipset voltage.
IN
Alternatively, this pin can be reconfigured as a bidirectional/omnidirectional THERM pin. Can be used to
time and monitor assertions on the THERM input. For example, can be connected to the PROCHOT
output of Intel's Pentium
an output to signal overtemperature conditions.
V
Analog Input. Monitors processor core voltage (0 V to 3 V).
CCP
Digital Output (Open Drain). Pulse width modulated output to control the speed of Fan 1. Requires 10 kW
typical pullup.
XTO
Also functions as the output from the XOR tree in XOR test mode.
ADT7476A
Description
®
4 processor or to the output of a trip point temperature sensor. Can be used as
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5
is also
CC
®
4
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