ADT7470

Data Sheet

Rev. E | Page 32 of 40

Table 34. Register 0x43. Fan Pulses per Revolution Register (Power-On Default = 0x55).

Bit Name

Read/Write

Description

[1:0] Fan 1

Read/Write

Sets the number of pulses to be counted when measuring Fan 1 speed.

Can be used to determine fan’s pulses per revolution number for unknown fan type.

Pulses Counted

00 = 1

01 = 2 (default)

10 = 3

11 = 4

[3:2] Fan 2

Read/Write

Sets the number of pulses to be counted when measuring Fan 2 speed.

Can be used to determine fan’s pulses per revolution number for unknown fan type.

Pulses Counted

00 = 1

01 = 2 (default)

10 = 3

11 = 4

[5:4] Fan 3

Read/Write

Sets the number of pulses to be counted when measuring Fan 3 speed.

Can be used to determine fan’s pulses per revolution for unknown fan type.

Pulses Counted

00 = 1

01 = 2 (default)

10 = 3

11 = 4

[7:6] Fan 4

Read/Write

Sets the number of pulses to be counted when measuring Fan 4 speed. Can be used to determine fan’s

pulses per revolution for unknown fan type.

Pulses Counted

00 = 1

01 = 2 (default)

10 = 3

11 = 4

Table 35. Register 0x44 to Register 0x57. Temperature Limit Registers.

Register Address

Read/Write

Description

Power-On Default

0x44

Read/Write

Temperature 1 low limit

0x81

0x45

Read/Write

Temperature 1 high limit

0x7F

0x46

Read/Write

Temperature 2 low limit

0x81

0x47

Read/Write

Temperature 2 high limit

0x7F

0x48

Read/Write

Temperature 3 low limit

0x81

0x49

Read/Write

Temperature 3 high limit

0x7F

0x4A

Read/Write

Temperature 4 low limit

0x81

0x4B

Read/Write

Temperature 4 high limit

0x7F

0x4C

Read/Write

Temperature 5 low limit

0x81

0x4D

Read/Write

Temperature 5 high limit

0x7F

0x4E

Read/Write

Temperature 6 low limit

0x81

0x4F

Read/Write

Temperature 6 high limit

0x7F

0x50

Read/Write

Temperature 7 low limit

0x81

0x51

Read/Write

Temperature 7 high limit

0x7F

0x52

Read/Write

Temperature 8 low limit

0x81

0x53

Read/Write

Temperature 8 high limit

0x7F

0x54

Read/Write

Temperature 9 low limit

0x81

0x55

Read/Write

Temperature 9 high limit

0x7F

0x56

Read/Write

Temperature 10 low limit

0x81

0x57

Read/Write

Temperature 10 high limit

0x7F

Exceeding any of the temperature limits shown in Table 35 by 1°C causes the appropriate status bit to be set in the interrupt status 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).