ADT7467 Analog Devices, Inc., ADT7467 Datasheet - Page 61

• Manufacturer Part Number: ADT7467
• Description: Dbcool Remote Thermal Monitor And Fan Controller
• Manufacturer: Analog Devices, Inc.

Address
0x79
0x7A
0x7B
0x7C
0x7D
0x7E
0x7F
Table 18. Voltage Reading Registers (Power-On Default = 0x00)
Register Address
0x21
0x22
1
2
3
Table 19. Temperature Reading Registers (Power-On Default = 0x01)
Register Address
0x25
0x26
0x27
1
2
3
4
Table 20. Fan Tachometer Reading Registers (Power-On Default = 0x00)
Register Address
0x28
0x29
0x2A
0x2B
0x2C
0x2D
0x2E
0x2F
1
If the extended resolution bits of these readings are also being read, the extended resolution registers (Reg. 0x76, 0x77) must be read first. Once the extended
resolution registers have been read, the associated MSB reading registers are frozen until read. Both the extended resolution registers and the MSB registers are
frozen.
If V
V
These temperature readings can be in twos complement or Offset 64 format; this interpretation is determined by Bit 0 of Configuration Register 5 (0x7C).
If the extended resolution bits of these readings are also being read, the extended resolution registers (Reg. 0x76, 0x77) must be read first. Once the extended
resolution registers have been read, all associated MSB reading registers get frozen until read. Both the extended resolution registers and the MSB registers are frozen.
In twos complement mode, a temperature reading of −128°C (0x80) indicates a diode fault (open or short) on that channel.
In Offset 64 mode, a temperature reading of −64°C (0x00) indicates a diode fault (open or short) on that channel.
These registers count the number of 11.11 μs periods (based on an internal 90 kHz clock) that occur between a number of consecutive fan TACH pulses (default = 2).
The number of TACH pulses used to count can be changed using the fan pulses per revolution register (Reg. 0x7B). This allows the fan speed to be accurately
measured. Because a valid fan tachometer reading requires that two bytes are read, the low byte must be read first. Both the low and high bytes are then frozen until
read. At power-on, these registers contain 0x0000 until the first valid fan TACH measurement is read into these registers. This prevents false interrupts from occurring
while the fans are spinning up.
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•
•
•
•
A count of 0xFFFF indicates that a fan is one of the following:
CC
CCP
(Pin 3) is the supply voltage for the ADT7467.
LO (Bit 1 of the Dynamic T
Stalled or blocked (object jamming the fan).
Failed (internal circuitry destroyed).
Not populated. (The ADT7467 expects to see a fan connected to each TACH. If a fan is not connected to a TACH, the minimum high and low bytes of that TACH
should be set to 0xFFFF.)
Alternate function (for example, TACH4 reconfigured as THERM pin).
2-wire instead of 3-wire fan.
R/W
R
R/W
R/W
R/W
R/W
R
R
Description
THERM timer
THERM timer limit
TACH pulses per
Configuration Register 5
Configuration Register 4
Test Register 1
Test Register 2
status register
register
revolution
MIN
R/W
Read only
Read only
R/W
Read only
Read only
Read only
R/W
Read only
Read only
Read only
Read only
Read only
Read only
Read only
Read only
Control Register 1, 0x36) is set, V
Bit 7
TMR
LIMT
FAN4
RES
RES
Description
Reflects the voltage measurement
Reflects the voltage measurement
Description
Remote 1 temperature reading
Local temperature reading (8 MSB of reading).
Remote 2 temperature reading (8 MSB of reading).
Description
TACH1 low byte.
TACH1 high byte.
TACH2 low byte.
TACH2 high byte.
TACH3 low byte.
TACH3 high byte.
TACH4 low byte.
TACH4 high byte.
Bit 6
TMR
LIMT
FAN4
RES
RES
CCP
can control the sleep state of the ADT7467.
Rev. A | Page 61 of 80
Bit 5
TMR
LIMT
FAN3
RES
BpAtt
V
DO NOT WRITE TO THESE REGISTERS
DO NOT WRITE TO THESE REGISTERS
CCP
1
1, 2
Bit 4
TMR
LIMT
FAN3
RES
RES
1
3, 4
(8 MSB of reading).
2
3
at the V
at the V
Bit 3
TMR
LIMT
FAN2
GPIOP
AINL
CCP
CC
input on Pin 3 (8 MSBs of reading).
input on Pin 14 (8 MSBs of reading).
Bit 2
TMR
LIMT
FAN2
GPIOD
AINL
Bit 1
TMR
LIMT
FAN1
LF/HF
Pin 9
Func
Bit 0
ASRT/T
MRO
LIMT
FAN1
Twos
Compl
Pin 9
Func
ADT7467
Default
0x00
0x00
0x55
0x00
0x00
0x00
0x00
Lock
-able
Yes
Yes
Yes
Yes