W83L784R_05 Datasheet, PDF(11/52 Page) Winbond

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W83L784R_05 Datasheet, PDF (11/52 Pages) Winbond – Monitoring IC

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W83L784R/ W83L784G

6. FUNCTIONAL DESCRIPTION

6.1 General Description

The W83L784R/G provides at most 4 analog positive inputs, 2 fan speed monitors, 2 sets for fan

PWM (Pulse Width Modulation) Smart Fan Control , 2 remote thermal inputs from remote thermistors

or 2N3904 transistors or PentiumTM II (Deschutes) thermal diode outputs and one on-chip thermal

detection. W83L784R/G also provides the power good (reset) output for 3V and 5V power detection

and two fault output pins issuing hardware warning if battery and fans become abnormal. When

starting the monitor function on the chip, the watch dog machine monitor every function and store the

value to registers. If the monitor value exceeds the limit value, the interrupt status will be set to 1.

6.2 Access Interface

The W83L784R/G provides I2C Serial Bus to read/write internal registers. In the W83L784R/G there

are three serial bus addresses. The first address defined at CR [4Ah] can read/write all registers

excluding CPUT1/CPUT2 temperature sensor registers and its address default value is 0101101. The

address for CPUT1 defined at CR [4Bh] bit2-0 only read/write CPUT1 temperature sensor registers

and the address default value is 1001001. The address for CPUT2 defined at CR [4Bh] bit2-0 only

read/write CPUT1 temperature sensor registers and the address default value is 1001000.

6.2.1 The first serial bus access timing is shown as follows:

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

SCL

780

SDA

Start By

Master

10110

Frame 1

Serial Bus Address Byte

SCL (Continued)

1 R/W

D7 D6 D5 D4 D3 D2 D1 D0

Ack

Frame 2

784R

Internal Index Register Byte

SDA (Continued)

D7 D6 D5 D4 D3 D2 D1 D0

Ack

784R

Frame 3

Data Byte

Stop

Master

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

(b) Serial bus write to internal address register only

SCL

780

SDA

Start By

Master

Frame 1

Serial Bus Address Byte

1 R/W

D7 D6 D5 D4 D3 D2 D1 D0

Ack

Frame 2

784R

Internal Index Register Byte

Ack

784R

Stop by

Master

Figure 2. Serial Bus Write to Internal Address Register Only

Publication Release Date: Jan. 2005

-6-

Revision 1.1

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