W83791G Nuvoton Technology Corporation of America, W83791G Datasheet - Page 17

• Manufacturer Part Number: W83791G
• Description: IC MONITOR H/W 48-LQFP
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of W83791G

• Function: Hardware Monitor
• Topology: ADC
• Sensor Type: External
• Sensing Temperature: External Sensor
• Output Type: I²C™
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

6. FUNCTION DESCRIPTION
6.1
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
Pentium
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
The W83791D/G provides I
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
(a) Serial bus writes to internal address register followed by the data byte
General Description
Access Interface
SCL
SDA
The first serial bus access timing
TM
II/III (Deschutes) thermal diode outputs, case open detection and beep function output
Start By
Master
0
0
Figure 1. Serial Bus Write to Internal Address Register followed by the Data Byte
1
Serial Bus Address Byte
0
SCL
SDA (Continued)
2
C Serial Bus for microprocessor to read/write internal registers. In the
Frame 1
1
(Continued)
1
0
1
R/W
0
D7
7
- 11 -
791D
Ack
8
D6
by
0
D7
D5
D6
D4
Internal Index Register Byte
D5
D3
Data Byte
Publication Release Date: April 14, 2006
Frame 3
Frame 2
D4
D2
D3
D1
D2
7
D0
784R
791D
Ack
Ack
D1
8
by
by
W83791D/G
7
D0
Master
Stop
by
791D
8
Ack
by
Revision 1.1