Analog Devices dBCool ADT7475 Manual page 62

ADT7475
Table 50. Register 0x7B—TACH Pulses per Revolution Register (Power-On Default = 0x55)
Bit Name R/W
<1:0> FAN1 Read/write
<3:2> FAN2 Read/write
<5:4> FAN3 Read/write
<7:6> FAN4 Read/write
Table 51. Register 0x7C—Configuration Register 5 (Power-On Default = 0x00)
1
Bit Name R/W
<0> 2sC Read/write
<1> TempOffset
<2> GPIOD
<3> GPIOP
<4> RES
<5> R1 THERM Read/write
Description
Sets number of pulses to be counted when measuring Fan 1 speed. Can be used to determine fan
pulses per revolution for unknown fan type.
Pulses Counted
00 = 1
01 = 2 (default)
10 = 3
11 = 4
Sets number of pulses to be counted when measuring Fan 2 speed. Can be used to determine fan
pulses per revolution for unknown fan type.
Pulses Counted
00 = 1
01 = 2 (default)
10 = 3
11 = 4
Sets number of pulses to be counted when measuring Fan 3 speed. Can be used to determine fan
pulses per revolution for unknown fan type.
Pulses Counted
00 = 1
01 = 2 (default)
10 = 3
11 = 4
Sets number of pulses to be counted when measuring Fan 4 speed. Can be used to determine fan
pulses per revolution for unknown fan type.
Pulses Counted
00 = 1
01 = 2 (default)
10 = 3
11 = 4
Description
Twos complement = 1, sets the temperature range to twos complement temperature range.
Twos complement = 0, changes the temperature range to Offset 64. When this bit is changed, the
ADT7475 interprets all relevant temperature register values as defined by this bit.
TempOffset = 0, sets offset range to −63°C to +64°C with 0.5˚C resolution.
TempOffset = 1, sets offset range to −63°C to +127°C with 1˚C resolution.
These settings apply to registers 0x70, 0x71, and 0x72 (remote 1, internal, and Remote 2 temperature
offset registers.
GPIO direction. When GPIO function is enabled, this determines whether the GPIO is an input (0) or an
output (1).
GPIO polarity. When the GPIO function is enabled and is programmed as an output, this bit
determines whether the GPIO is active low (0) or high (1).
Reserved
R1 THERM = 0 , THERM temperature limit functionality enabled for Remote 1 temperature channel.
THERM can also be disabled on any channel by the following:
In offset 64 mode, writing −64˚C to the appropriate THERM temperature limit.
In twos complement mode, writing −128˚C to the appropriate THERM temperature limit.
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