Datasheet

Functional Description
Intel® Xeon® Processor D-1500 Product Family 163
Datasheet - Volume 1 of 4: Integrated Platform Controller Hub
March 2015
The comparator checks if the device is within the specified range, including the limits.
For example, a device that is at 100 degrees when the upper limit is 100 will not trigger
the alert. Likewise, a device that is at 70 degrees when the lower limit is 70 will not
trigger
the alert.
The compares are done only on devices that have been enabled by BIOS for checking.
The compares are done in firmware, so all the compares are executed in one software
loop and at the end, if there is any out of bound temperature, Intel® Xeon® Processor
D-1500 Product Family’s TEMP_ALERT# signal is asserted.
When the external controller sees the TEMP_ALERT# signal low, it knows the device is
out of range. It can read the temperature and then change the limit for the device. It
may take up to 250 ms before the actual writes cause the signal to change state. For
instance, if Intel® Xeon® Processor D-1500 Product Family is at 105 degrees and the
limit is 100, the alert is triggered. If the controller changes the limits to 110, the
TEMP_ALERT# signal may remain low until the next thermal sampling window (every 1
ms) occurs and only then go high, assuming Intel® Xeon® Processor D-1500 Product
Family was still within its limits.
At boot, the controller can monitor the TEMP_ALERT# signal state. When BIOS has
finished all the initialization and enabled the temperature comparators, the
TEMP_ALERT# signal will be asserted since the default state of the limit registers is 0h;
hence, when Intel® Xeon® Processor D-1500 Product Family first reads temperatures,
they will be out of range. This is the positive indication that the external controller may
now read thermal information and get valid data. If the TEMP_ALERT# signal is enabled
and not asserted within 30 seconds after PLTRST#, the external controller should
assume there is a fatal error and handle accordingly. In general the TEMP_ALERT#
signal will assert within a 1–4 seconds, depending on the actual BIOS implementation
and flow.
Note: The TEMP_ALERT# assertion is only valid when PLTRST# is de-asserted. The controller
should mask the state of this signal when PLTRST# is asserted. Since the controller
may be powered even when Intel® Xeon® Processor D-1500 Product Family and the
rest of the platform are not, the signal may glitch as power is being asserted; thus, the
controller should wait until PLTRST# has de-asserted before monitoring the signal.
3.21.3.5.1 Special Conditions
The external controller should have a graceful means of handling when TEMP_ALERT#
asserts, and the controller reads Intel® Xeon® Processor D-1500 Product Family, but
all temperature values are within limits. In this case, the controller should assume that
by the time the controller could read the data, it had changed and moved back within
the limits.
3.21.3.6 BIOS Set Up
In order for Intel® Xeon® Processor D-1500 Product Family to properly report
temperature and enable alerts, the BIOS must configure Intel® Xeon® Processor D-
1500 Product Family at boot or from suspend/resume state by writing the following
information to Intel® Xeon® Processor D-1500 Product Family MMIO space. This
information is NOT configurable using the external controller.
• Enables for Intel® Xeon® Processor D-1500 Product Family thermal alerts.
• Enables for reading Intel® Xeon® Processor D-1500 Product Family temperatures.