Datasheet

LM87

www.ti.com

SNAS034J –APRIL 2000–REVISED MARCH 2013

Model Number Frame Size Airflow CFM

(80 mm sq. X 25 mm)

REGISTERS AND RAM

13.1 Address Pointer Register

The main register is the Address Pointer Register. The bit designations are as follows:

Bit Name Read/Write Description

7-0 Address Pointer Write Address of RAM and Registers. See the tables below for detail.

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Address Pointer (Power On default 00h)

A7 A6 A5 A4 A3 A2 A1 A0

Address Pointer Index (A7–A0)

Registers and RAM A6–A0 in Hex Power On Value of Registers: Notes

<7:0> in Binary

Internal Temp. Hardware High 13h 0100 0110 70 °C Default - <7:0>=0100 0110 - User

Limit adjustable. Lockable by setting bit 1 of register

4Ah.

External Temp. Hardware High 14h 0101 0101 85 °C Default - <7:0>=0101 0101 - User

Limit adjustable. Lockable by setting bit 2 of register

4Ah.

Test Register 15h 0000 0000 Always set to 00h

Channel Mode Register 16h 0000 0000

Internal Temp. Hardware High 17h 0100 0110 70 °C Default - <7:0>=0100 0110 - User

Limit adjustable

External Temp. Hardware High 18h 0101 0101 85 °C Default - <7:0>=0101 0101 - User

Limit adjustable

Value RAM 19h–3Dh See Value RAM—Address 19h–3Fh for details.

Address 19h default=1111 1111

Company ID 3Eh 0000 0010 This designates the Texas Instruments LM87.

Revision 3Fh 0000 0110 Revisions of this device will start with 1 and

increment by one.

Configuration Register 1 40h 0000 1000

Interrupt Status Register 1 41h 0000 0000

Interrupt Status Register 2 42h 0000 0000

Interrupt Mask Register 1 43h 0000 0000

Interrupt Mask Register 2 44h 0000 0000

CI Clear Register 46h 0000 0000

VID0-3/Fan Divisor 47h <7:4> = 0101;

VID4 Register 49h <7:1> =1000 000; <0>=VID4

Configuration Register 2 4Ah 0000 0000

Interrupt Status Register 1 Mirror 4Ch 0000 0000

Interrupt Status Register 2 Mirror 4Dh 0000 0000

SMBALERT# Enable 80h 0010 0000

Product Folder Links: LM87