W83L786NR Datasheet, PDF (13/50 Pages) Winbond – H/W Monitoring IC

W83L786NR/ W83L786NG
7. FUNCTIONAL DESCRIPTION
7.1 General Description
The W83L786NR/NG provides 3 analog voltage inputs, 2 fan speed inputs and outputs which support
both PWM (Pulse Width Modulation) fan control and DC (Direct Current) fan control, all of them being
implemented with SMART FAN^TM I and SMART FAN^TM II, and 2 sets of thermal inputs for CPU/GPU
thermal diode sensor or remote temperature sensor. W83L786NR/NG is I²C / SMBus interface
compatible. Furthermore, the Watch Dog Timer will monitor every function and store the values to
registers for comparison with preset ranges. If the monitored value exceeds the limit value, the
interrupt status will be set to 1 and W83L786NR/NG will issue interrupt signals such as INT# and IRQ
if not masked. W83L786NR/NG also provides software and hardware Watch Dog Timer to avoid
system hang on.
7.2 Access Interface
The W83L786NR/NG provides I²C Serial Bus for microprocessor to read/write internal registers, and
the I²C address default value is 01011110b (Pin 6 pull high). If Pin 6 pulls low, the I²C address value is
01011100b.
7.3 The First Serial Bus Access Timing
(a) Serial bus writes to internal address register followed by the data byte
0
SCL
780
78
SDA
0
Start By
Master
10110
Frame 1
Serial Bus Address Byte
SCL (Continued)
1 R/W
D7 D6 D5 D4 D3 D2 D1 D0
Ack
Ack
by
by
Frame 2
792D
792D
Internal Index Register Byte
0
78
SDA (Continued)
D7 D6 D5 D4 D3 D2 D1 D0
Frame 3
Data Byte
Ack
by
79824DR
Stop
by
Master
Figure 1. Serial Bus Write to Internal Address Register followed by the Data Byte
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