W83627UHG Nuvoton Technology Corporation of America, W83627UHG Datasheet - Page 48

• Manufacturer Part Number: W83627UHG
• Description: IC I/O CONTROLLER 128-QFP
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of W83627UHG

• Applications: PC's, PDA's
• Interface: LPC
• Voltage - Supply: 3.3V, 5V
• Package / Case: 128-XFQFN
• Mounting Type: Surface Mount
• Pin Count: 128
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

7.5
PECI (Platform Environment Control Interface) is a proprietary derivation of SST. It is one of the
temperature sensing methods that the W83627UHG supports. With a bandwidth ranging from 2 kbps
to 2 Mbps, PECI uses a single wire – no additional control lines needed – for self-clocking and data
transfer. By interfacing to Digital Thermal Sensor on the Intel
temperature value relative to the processor’s temperature at which the thermal control circuit (TCC) is
activated.
To enable the PECI functionalities of the W83627UHG, BIOS/software should follow the steps below:
1. Program Logical Device C, CR[E8h] bit (1..0) for PECI speed selection to meet the bit timing limits
of CPU with PECI. “11b” is recommended to be set to the bit for better stability.
5. Since the PECI temperature is a relative value, the W83627UHG provides registers for each PECI
Agent to convert the relative value to a more traditional “absolute” format. The TBase registers
(Logical Device C, CR[E1h]~CR[E4h]) store the “base” temperature. By means of BIOS/software, the
desired base temperature can be written to these registers. Important: the value must be positive.
Otherwise abnormal temperature responses will take place. Here is an example on how to obtain
TBase value:
(1). Use a digital thermometer on the surface of the PECI processor to measure the processor body
temperature.
(2). Power up the system with the PECI processor. Run the processor to 100% loading.
(3). After the system is stable, read the PECI reading from Logical Device C, CR[E0h] ~ CR[E7h] of
selected Agents and record the value of the digital thermometer.
(4). Calculate TBase. For example, if PECI = -10 and the digital thermometer is 50’C, then TBase
could be set to 60’C. (60 – 10 = 50).
7. The temperature values in Bank 1 and Bank 2 Index 50h & 51h are:
Bank 1, Index 50h & 51h = (TBase) + (PECI Agent relative temperature)
Bank 2, Index 50h & 51h = (TBase) + (PECI Agent relative temperature)
selects PECI Agent 1 as the temperature source, the reported temperature will be 62°C (-10 + 72).
2. Program Logical Device C, CR[E5h] bit (7..4) for each PECI Agent to match the number of
domains in the processors. Setting to “1” enables the W83627UHG to issue GetTemp(0) and
GetTemp(1) commands to access the PECI temperatures of domains 0 and domain 1. Setting to “0”
enables the W83627UHG to issue GetTemp(0) command for domain 0.
3. Program Logical Device C, CR[E0h] bit (3..0) for each PECI Agent. Setting to “1” returns the PECI
temperature of domain 1 to the temperature reading register. Setting to “0” returns the PECI
temperature of domain 0 to the temperature reading register. If CR[E5h] bit 1 is set to “1”, the higher
PECI temperature of domain 0 and domain 1 is returned to the temperature reading register. See the
example below for more details about the temperature reading register(s)
4. Program Logical Device C, CR[E0h] bit (7..4) for each PECI Agent. Setting to “1” enables the
W83627UHG to access the agent. The power-on default is disabled. After an agent is enabled, the
W83627UHG issues PING and GetTemp commands to obtain the PECI temperature.
6. There are two temperature reading registers in the W83627UHG: Bank1, Index 50h & 51h, and
Bank2, Index 50h & 51h. The source of the Bank 1, Index 50h & 51h value is determined by the
value programmed into the CPUFANOUT monitor Temperature source select register (Hardware
Monitor Device, Bank 0, Index 49h, bits (2..0)). The source of Bank 2, Index 50h & 51h value is
determined by the value programmed into the SYSFANOUT monitor Temperature source select
register (Hardware Monitor Device, Bank 0, Index 4Ah, bits(7..5)).
Example:
If the PECI relative temperature of agent 1 is -10; TBase is set to 72°C, and Bank0 Index 49h
PECI
-33-
Publication Release Date: March 24, 2008
®
CPU, PECI reports a negative
W83627UHG
Revision 1.44