Dmi2 Link Down; Platform Environment Control Interface (Peci) - Intel BX80619I73960X Datasheet

2.3.2

DMI2 Link Down

The DMI2 link going down is a fatal, unrecoverable error. If the DMI2 data link goes to
data link down, after the link was up, then the DMI2 link hangs the system by not
allowing the link to retrain to prevent data corruption. This is controlled by the PCH.
Downstream transactions that had been successfully transmitted across the link prior
to the link going down may be processed as normal. No completions from downstream,
non-posted transactions are returned upstream over the DMI2 link after a link down
event.
2.4

Platform Environment Control Interface (PECI)

The Platform Environment Control Interface (PECI) uses a single wire for self-clocking
and data transfer. The bus requires no additional control lines. The physical layer is a
self-clocked one-wire bus that begins each bit with a driven, rising edge from an idle
level near zero volts. The duration of the signal driven high depends on whether the bit
value is a logic '0' or logic '1'. PECI also includes variable data transfer rate established
with every message. In this way, it is highly flexible even though underlying logic is
simple.
The interface design was optimized for interfacing to Intel processor and chipset
components in both single processor and multiple processor environments. The single
wire interface provides low board routing overhead for the multiple load connections in
the congested routing area near the processor and chipset components. Bus speed,
error checking, and low protocol overhead provides adequate link bandwidth and
reliability to transfer critical device operating conditions and configuration information.
Refer to the processor Thermal Mechanical Specification and Design Guide (see
Section 1.7, "Related
supported PECI commands.
20
Documents") for additional details regarding PECI and for a list of
§
Interfaces
Datasheet, Volume 1