ADT7475 Analog Devices, Inc., ADT7475 Datasheet - Page 54

• Manufacturer Part Number: ADT7475
• Description: Dbcool Remote Thermal Monitor And Fan Controller
• Manufacturer: Analog Devices, Inc.

ADT7475
Table 25. Register 0x42—Interrupt Status Register 2 (Power-On Default = 0x00)
Bit
[1]
[2]
[3]
[4]
[5]
[6]
[7]
Table 26. Voltage Limit Registers
Register Address
0x46
0x47
0x48
0x49
1
2
Table 27. Temperature Limit Registers
Register Address
0x4E
0x4F
0x50
0x51
0x52
0x53
1
2
Table 28. Fan Tachometer Limit Registers
Register Address
0x54
0x55
0x56
0x57
0x58
0x59
0x5A
0x5B
1
Setting the Configuration Register 1 lock bit has no effect on these registers.
High limits: an interrupt is generated when a value exceeds its high limit (> comparison); low limits: an interrupt is generated when a value is equal to or below its low
limit (≤ comparison).
Exceeding any of these temperature limits by 1°C causes the appropriate status bit to be set in the interrupt status register. Setting the Configuration Register 1 lock
bit has no effect on these registers.
High limits: an interrupt is generated when a value exceeds its high limit (> comparison); low limits: an interrupt is generated when a value is equal to or below its low
limit (≤ comparison).
Exceeding any of the TACH limit registers by 1 indicates that the fan is running too slowly or has stalled. The appropriate status bit is set in Interrupt Status Register 2
to indicate the fan failure. Setting the Configuration Register 1 lock bit has no effect on these registers.
Name
OVT
FAN1
FAN2
FAN3
F4P
D1
D2
R/W
Read-only
Read-only
Read-only
Read-only
Read-only
R/W
Read-only
Read-only
Read-only
D1 = 1 indicates either an open or short circuit on the Thermal Diode 1 inputs.
D2 = 1 indicates either an open or short circuit on the Thermal Diode 2 inputs.
R/W
R/W
R/W
R/W
Description
OVT = 1 indicates that one of the THERM overtemperature limits has been exceeded. This bit is cleared on a
read of the status register when the temperature drops below THERM – T
FAN1 = 1 indicates that Fan 1 has dropped below minimum speed or has stalled. This bit is not set when the
PWM1 output is off.
FAN2 = 1 indicates that Fan 2 has dropped below minimum speed or has stalled. This bit is not set when the
PWM2 output is off.
FAN3 = 1 indicates that Fan 3 has dropped below minimum speed or has stalled. This bit is not set when the
PWM3 output is off.
F4P = 1 indicates that Fan 4 has dropped below minimum speed or has stalled. This bit is not set when the
PWM3 output is off.
When Pin 9 is programmed as a GPIO output, writing to this bit determines the logic output of the GPIO.
If Pin 9 is configured as the THERM timer input for THERM monitoring, this bit is set when the THERM
assertion time exceeds the limit programmed in the THERM timer limit register (0x7A).
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
1
1
Description
V
V
V
V
Description
Remote 1 temperature low limit.
Remote 1 temperature high limit.
Local temperature low limit.
Local temperature high limit.
Remote 2 temperature low limit.
Remote 2 temperature high limit.
Description
TACH1 minimum low byte.
TACH1 minimum high byte/single-channel ADC channel select.
TACH2 minimum low byte.
TACH2 minimum high byte.
TACH3 minimum low byte.
TACH3 minimum high byte.
TACH4 minimum low byte.
TACH4 minimum high byte.
1
CCP
CCP
CC
CC
low limit.
high limit.
low limit.
high limit.
2
2
Rev. B | Page 54 of 68
HYST
.
Power-On Default
0xFF
0xFF
0xFF
0xFF
0xFF
0xFF
0xFF
0xFF
Power-On Default
0x00
0xFF
0x00
0xFF
Power-On Default
0x81
0x7F
0x81
0x7F
0x81
0x7F