Intel BX80619I73820, Design Manual, Page: 76 / 124

PECI Interface
76 Thermal/Mechanical Specifications and Design Guide
7.1.4 ACPI P-T Notify Read/Write
This interface coupled with limiting OSPM usage of P-States using ACPI _PPC object and
programming of the package power limit registers enables turbo capability while
limiting maximum package power dissipation to be within the specified package power
limit.
7.1.4.1 Thermally Constrained Time Read
This features allows the PECI host to access the total time for which the processor has
been operating in a lowered power state due to TCC activation. The returned data
includes the time required to ramp back up to the original P-state target after TCC
activation expires. This timer does not include TCC activation as a result of an external
assertion of PROCHOT_N. This is tracked by a 32-bit counter that rolls over or wraps
around. Note that on the processor PECI clients, the only logic that can be thermally
constrained is that supplied by V
CC
.
7.1.4.2 Current Limit Read
This read returns the current limit for the processor V
CC
power plane in 1/8A
increments. Actual current limit data is contained only in the lower 13 bits of the
response data. The default return value of 0x258 corresponds to a current limit value of
75 A.
7.1.4.3 Accumulated Energy Status Read
This service can return the value of the total energy consumed by the entire processor
package or just the logic supplied by the V
CC
power plane as specified through the
parameter field in Table 7-8 . This information is tracked by a 32-bit counter that wraps
around and continues counting on reaching its limit. Energy units for this read are
determined as per the Package Power SKU Unit settings described in
Section 7.1.2.7.2 .
Figure 7-30. Current Config Limit Read Data
Current Config Limit Data
RESERVED
13 31
Current Limit for processor VCC
12 0
Figure 7-31. Accumulated Energy Read Data
Accumulated Energy Status
Accumulated CPU Energy
0
31