7.1.2 LM64 Register Map in Functional Order

The following is a Register Map grouped in Functional Order. Some address locations have been left blank to

maintain compatibility with LM86. Addresses in parenthesis are mirrors of named address. Reading or writing

either address will access the same 8-bit register. The Fan Control and Configuration Registers are listed first,

as there is a required order to setup these registers first and then setup the others. The detailed explanations of

each register will follow the order shown below. POR = Power-On-Reset.

Register

[HEX]

Register Name

Read/Write

POR Default

[HEX]

FAN CONTROL REGISTERS

4A

PWM and RPM

R/W

20

4B

Fan Spin-Up Configuration

R/W

3F

4D

PWM Frequency

R/W

17

4C

PWM Value

Read Only

(R/W if Override Bit is Set)

00

50–5F

Lookup Table

R/W

See Table

4F

Lookup Table Hysteresis

R/W

04

CONFIGURATION REGISTER

03 (09)

Configuration

R/W

00

TACHOMETER COUNT AND LIMIT REGISTERS

46

Tach Count LSB

Read Only

N/A

47

Tach Count MSB

Read Only

N/A

48

Tach Limit LSB

R/W

FF

49

Tach Limit MSB

R/W

FF

LOCAL TEMPERATURE AND LOCAL SETPOINT REGISTERS

00

Local Temperature

Read Only

N/A

05 (0B)

Local High Setpoint

R/W

46 (70°)

REMOTE DIODE TEMPERATURE AND SETPOINT REGISTERS

01

Remote Temperature MSB

Read Only

N/A

10

Remote Temperature LSB

Read Only

N/A

11

Remote Temperature Offset MSB

R/W

00

12

Remote Temperature Offset LSB

R/W

00

07 (0D)

Remote High Setpoint MSB

R/W

46 (70°C)

13

Remote High Setpoint LSB

R/W

00

08 (0E)

Remote Low Setpoint MSB

R/W

00 (0°C)

14

Remote Low Setpoint LSB

R/W

00

19

Remote TCRIT Setpoint

R/W

55 (85°C)

21

Remote TCRIT Hys

R/W

0A (10°C)

BF

Remote Diode Temperature Filter

R/W

00

CONVERSION AND ONE-SHOT REGISTERS

04 (0A)

Conversion Rate

R/W

08

0F

One-Shot

Write Only

N/A

ALERT STATUS AND MASK REGISTERS

02

ALERT Status

Read Only

N/A

16

ALERT Mask

R/W

A4

ID REGISTERS

FE

Manufacturer's ID

Read Only

01

FF

Stepping/Die Rev. ID

Read Only

51

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LM64

SNAS207B – MAY 2004 – REVISED JANUARY 2024

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