LM81 datasheet(29/33 Pages) NSC

29 / 33 page

Functional Description (Continued)

13.10 VID/Fan Divisor Register — Address 47h

Power on default – <7:4> is 0101, and <3:0>is mapped to VID <3:0>

Bit

Name

Read/Write

Description

0-3

VID <3:0>

Read Only

The VID <3:0> inputs from the Pentium/PRO power supplies that indicate the

operating voltage (e.g. 1.5V to 2.9V).

4-5

FAN1 RPM

Control

Read/Write

FAN1 Speed Control.

<5:4> = 00 - divide by 1;

<5:4> = 01 - divide by 2;

<5:4> = 10 - divide by 4;

<5:4> = 11 - divide by 8.

6-7

FAN2 RPM

Control

Read/Write

FAN2 Speed Control.

<7:6> = 00 - divide by 1;

<7:6> = 01 - divide by 2;

<7:6> = 10 - divide by 4;

<7:6> = 11 - divide by 8.

13.11 Serial Bus Address Register — Address 48h

Power on default – Serial Bus address <6:0> = 010 11(A1)(A0) and <7> = 0 binary

Bit

Name

Read/Write

Description

0-1

Serial Bus

Address

Read Only

Serial Bus address <1:0> =A1 A0

2-6

Serial Bus

Address

Read/Write

Serial Bus address <6:2> = 010 11

Reserved

Read/Write

13.12 VID4 Register — Address 49h

Power on default – <7:1> = 100 000, <0> = VID4.

Bit

Name

Read/Write

Description

VID4

Read Only

VID4 input from Pentium/PRO power supply that indicate the operating voltage of

the processor (e.g. 1.5V to 2.9V).

1-7

Reserved

Read/Write

13.13 Temperature Configuration Register — Address 4Bh

Power on default – <7:0> = 0000 0001 binary

Bit

Name

Read/Write

Description

0-1

Temperature

Interrupt Mode

Select Bits

Read/Write

The state of these bits select the interrupt mode for INT as described below.

<1:0> =00 or <1:0> = 11: Repetitive Interrupt Mode

<1:0> = 01: One-Time Interrupt Mode

<1:0> = 10: Comparator Mode

2-6

Reserved

Read/Write

Temperature

Resolution

Read Only

For 8-bit plus sign temperature resolution: <7> = LSB ( 0.5˚C)

LM81 Datasheet(PDF) 29 Page - National Semiconductor (TI)

LM81 Datasheet(HTML) 29 Page - National Semiconductor (TI)

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33

Datasheet Download

Link URL