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W83627UHG
7.3.3.3.
Monitor Temperature from Thermal Diode (Current Mode)
The W83627UHG also can measure diode temperature by current mode and the circuit is shown in
the following figure.
W83627UHG
CPUTIN
(SYSTIN)
AGND
C= 2200pF
D+
D-
Thermal
Diode
Figure 7-7 Monitoring Temperature from Thermal Diode
The pin of processor D- is connected to AGND (pin 105) and the pin D+ is connected to temperature
sensor pin in W83627UHG. A bypass capacitor C=2200pF should be added to filter the high
frequency noise. The configuration registers to select a thermal diode temperature sensor and the
measurement method are found at Bank 0, Index 59h, 5Dh, and 5Eh.
7.4
SST Command Summary
The W83627UHG can act as an SST peripheral or slave and output the results of the Analog to Digital
Converter onto the SST bus. SST is a new, popular standard to communicate temperature and
voltage information from around the PC motherboard to report on the status of the system and control
cooling fans and other safety mechanisms.
SST is a self-clocked, one-wire bus for data transfer. The bus requires no additional control lines. In
addition, SST also includes variable data transfer rate established with every message. Therefore, it is
comparatively flexible. The W83627UHG has a programmable SST address defined at Logical Device
C CR[F1h]. The default address is 0x48h which is within the range of 0x48h-0x4ah defined in the SST
specification.
Since the same, integrated Analog to Digital Converter is used, all the features and restrictions of use
remain the same. The reference voltage is integrated and fixed with the 8-bit ADC, yielding a
maximum voltage on each of 2.048V and an LSB of 8mV. As discussed in the previous section 7.3,
voltage scaling using resistive dividers may be necessary to keep external voltages within the
maximum input voltage range. The power supply pins have integrated resistive dividers.
7.4.1 Command Summary
The W83627UHG supports SST commands as shown in the following table:
Publication Release Date: March 24, 2008
-30-
Revision 1.44