W83791G Datasheet, PDF(17/99 Page) Winbond – Winbond H/W Monitoring IC

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

W83791G Datasheet, PDF (17/99 Pages) Winbond – Winbond H/W Monitoring IC

◁

W83791D/G

6. FUNCTION DESCRIPTION

6.1 General Description

The W83791D/G provides 10 analog positive inputs, 5 fan speed inputs , at most 5 sets for fan PWM

(Pulse Width Modulation) control, 3 thermal inputs from remote thermistors, 2N3904 transistors or

PentiumTM II/III (Deschutes) thermal diode outputs, case open detection and beep function output

when the monitored values exceed preset ranges, including the voltage, temperature, and fan count.

Moreover, W83791D/G uniquely provides several innovative and practical functions to make the whole

system more efficient and compliant with future trend of network management, such as speech

function, ASF sensor compliant, SMBus 2.0 ARP command compatible, VID table selection trapping,

5VID output control, and so forth. Once the monitoring function of W83791D/G is enabled, the watch

dog machine will monitor every function and store the values to registers for comparison with preset

ranges. If the monitoring value exceeds the limit value, the interrupt status will be set to 1 and

W83791D/G will issue interrupt signals such as SMI# and IRQ if not masked..

6.2 Access Interface

The W83791D/G provides I2C Serial Bus for microprocessor to read/write internal registers. In the

W83791D/G, there are three serial bus addresses. Through the first address defined at CR [48h], all

the registers can be read and written except CPUT1/CPUT2 temperature sensor registers. The

read/write of the CPUT1/CPUT2 temperature sensor registers can be implemented through the

second address (defined at CR [4Ah] bit2-0) and the third address (defined at CR [4Ah] bit6-4).

The first serial bus address of W83791D/G has 2 hardware setting bits set by pin10-11. The address

is 001011[pin11], and [pin10]. Hence, the content of CR [48h] would be 00101110 if pin11=1 and

pin10=0.

6.2.1 The first serial bus access timing

(a) Serial bus writes to internal address register followed by the data byte

SCL

SDA

780

Start By

Master

10110

Frame 1

Serial Bus Address Byte

SCL (Continued)

SDA (Continued)

1 R/W

D7 D6 D5 D4 D3 D2 D1 D0

Ack

Frame 2

791D

Internal Index Register Byte

D7 D6 D5 D4 D3 D2 D1 D0

Frame 3

Data Byte

Ack

79814DR

Stop

Master

Figure 1. Serial Bus Write to Internal Address Register followed by the Data Byte

- 11 -

Publication Release Date: April 14, 2006

Revision 1.1

▷