ADM1031

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24

Table 13. Value Registers

Address

R/W

Description

0x06

R

Extended Temperature Resolution (see Table 18).

0x08

R/W

Fan 1 Speed. This register contains the value of the Fan 1 tach measurement.

0x09

R/W

Fan 2 Speed. This register contains the value of the Fan 2 tach measurement.

0x0A

R

Local Temperature Value. This register contains the 8 MSBs of the local temperature measurement.

0x0B

R

Remote 1 Temperature Value. This register contains the 8 MSBs of the Remote 1 temperature reading.

0x0C

R

Remote 2 Temperature Value. This register contains the 8 MSBs of the Remote 2 temperature reading.

0x0D

R/W

Local Temperature Offset. See Table 27. (Power−On Default = 00h)

0x0E

R/W

Remote 1 Temperature Offset. See Table 28. (Power−On Default = 00h)

0x0F

R/W

Remote 2 Temperature Offset. See Table 29. (Power−On Default = 00h)

0x10

R/W

Fan 1 Tach High Limit. This register contains the limit for the Fan 1 tach measurement. Because the tach

circuit counts between pulses, a slow fan results in a large measure value, so exceeding the limit is the

way to detect a slow or stalled fan. (Power−On Default = FFh)

0x11

R/W

Fan 2 Tach High Limit. This register contains the limit for the Fan 2 tach measurement. Because the tach

circuit counts between pulses, a slow fan results in a large measured value, so exceeding the limit is the

way to detect a slow or stalled fan. (Power−On Default = FFh)

0x14

R/W

Local Temperature High Limit (Power−On Default 60°C)

0x15

R/W

Local Temperature Low Limit (Power−On Default 0°C)

0x16

R/W

Local Temperature THERM Limit (Power−On Default 70°C)

0x18

R/W

Remote 1 Temperature High Limit (Power−On Default 80°C)

0x19

R/W

Remote 1 Temperature Low Limit (Power−On Default 0°C)

0x1A

R/W

Remote 1 Temperature THERM Limit (Power−On Default 100°C)

0x1C

R/W

Remote 2 Temperature High Limit (Power−On Default 80°C)

0x1D

R/W

Remote 2 Temperature Low Limit (Power−On Default 0°C)

0x1E

R/W

Remote 2 Temperature THERM Limit (Power−On Default 100°C)

Table 14. Register 0y00 Configuration Register 1 Power−On Default = 90H

Bit

Name

R/W

Description

0

MONITOR

R/W

Setting this bit to a “1” enables monitoring of temperature and enables measurement

of the fan tach signals. (Powerup Default=0)

1

INT Enable

R/W

Setting this bit to a “1” enables the INT output. 1= Enabled 0= Disabled

(Powerup Default=0)

2

TACH/AIN

R/W

Clearing this bit to “0” selects digital fan speed measurement via the TACH pins.

Setting this bit to “1” configures the TACH pins as analog inputs that can measure the

speed of 2−wire fans via a sense resistor. (Powerup Default=0)

3

PWM Invert

R/W

Setting this bit to “1” inverts the PWM signal on the output pins. (Powerup Default=0)

4

FAN_FAULT Enable

R/W

Logic 1 enables FAN_FAULT pin; Logic 0 disables FAN_FAULT output.

(Powerup Default=1)

6−5

PWM Mode

R/W

These two bits control the behavior of the fans in auto fan speed control mode.

00 = Remote Temp 1 controls Fan 1; Remote Temp 2 controls Fan 2.

01 = Remote Temp 1 controls Fan 1 and Fan 2.

10 = Remote Temp 2 controls Fan 1 and Fan 2.

11 = Max of Local Temp and Remote Temp 1 and 2 drives Fans 1 and 2.

These two bits have the following effect in software control mode.

00 = Program PWM duty cycles for Fans 1 and 2.

11 = Program RPM Speeds for Fans 1 and 2.

7

Auto/SW Ctrl

R/W

Logic 1 selects automatic fan speed control; Logic 0 selects SW control. (Powerup

Default = 1). When under software control, PWM duty cycle or RPM values can be

programmed for each fan.