NCT6627UD Nuvoton Technology Corporation of America, NCT6627UD Datasheet - Page 48

• Manufacturer Part Number: NCT6627UD
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of NCT6627UD

• Lead Free Status / Rohs Status: Supplier Unconfirmed

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 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) “+2.5V” = Decimal[2-byte data by GetVolt2p5V()] / 1024 / ((R5+R6) / R6) volts
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.
VIN2 (pin 98) is connected as shown below:
PECI
3VCC
2.5V
R3
10K 1%
R5
10K 1%
®
CPU, PECI reports a negative temperature value relative to the processor’s
R4
10K 1%
R6
10K 1%
VIN1
VIN2
AGND
AGND
1
1
1
1
-39-
W83627UHG/NCT6627UD
Publication Release Date: October 26, 2010
Revision 1.7