KC82870DH S L5X2 Intel, KC82870DH S L5X2 Datasheet - Page 33

• Manufacturer Part Number: KC82870DH S L5X2
• Manufacturer: Intel

Specifications of KC82870DH S L5X2

• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Not Compliant

4.4
4.4.1
4.4.2
Intel
®
E8870DH DDR Memory Hub (DMH) Datasheet
Note: One DDR clock cycle may be stretched during this procedure if the DMH stalls its internal clock to
Note: Unlike MCP packets, there is no Command Type Field (ST, SF) for this packet. The DMH
bring its MCP state tracker into sync.
specifically expects to receive a time sync packet only during a certain point in RAC Initialization
mode.
Main Channel Periodic Calibration
The Main Channel RAC must be calibrated on a periodic basis to prevent timing violations that
could occur as a result of variations in voltage and temperature over time. Periodic current and
temperature calibration will sufficiently compensate for these variations. Periodic Branch Channel
calibration is embedded within the Main Channel calibration events as described in
“Branch Channel Periodic Calibration.”
Current Calibration
The DMH provides a long current calibration and a periodic current calibration procedure. The
long current calibration procedure is for reset initialization.
BIOS performs a long current calibration once after reset through an initialization calibration
sequence that takes approximately 6 s to complete (see
BIOS accesses the long current calibration controls through the RIR register (see
– RAC Initialization
during the 6 s calibration interval.
Temperature Calibration
Main Channel temperature calibration provides a mechanism to dynamically compensate the
output driver slew-rate for changes in temperature. The DMH provides two methods of access to
the temperature calibration procedure. One method is used for reset initialization by BIOS, the
other is used for autonomous periodic calibration by the SNC.
BIOS performs a temperature calibration once after reset as part of its RAC initialization sequence
(see
Initialization
temperature calibration event. The RAC initialization operation (used in the procedure) performs a
RAC temperature calibration within its sequence of events. Optionally, the RIR register provides a
RAC temperature calibration operation as well. The Main Channel and Branch Channels should
remain quiescent until the serial command completes.
Temperature calibration is also performed periodically by an autonomous timer function within the
SNC. The SNC sends temperature calibration MCPs at intervals of 100 ms or less. Upon receiving
the Temperature Calibrate MCP (see
Main Channel, the DMH initiates the RAC temperature calibration process as well as the Branch
Channel slew rate calibration (see
Section 4.14.1, “RAC
Register”) used in this procedure provides two different methods for invoking the
Register”). The Main Channel and Branch Channels must remain quiescent
Initialization”). The RIR register (see
Section 4.5.1, “Slew Rate
Section 4.2.5, “MCP for Extended
Section 4.14.1, “RAC
Calibration”).
Section 3.9, “RIR – RAC
Commands”) from the
Functional Description
Initialization”).
Section 3.9, “RIR
Section 4.5,
4-5