Intel BX80646I74770S Computer Hardware User Manual


 
5 GT/s point-to-point DMI interface to PCH is supported.
Raw bit-rate on the data pins of 5.0 GB/s, resulting in a real bandwidth per pair of
500 MB/s given the 8b/10b encoding used to transmit data across this interface.
Does not account for packet overhead and link maintenance.
Maximum theoretical bandwidth on interface of 2 GB/s in each direction
simultaneously, for an aggregate of 4 GB/s when DMI x4.
Shares 100-MHz PCI Express* reference clock.
64-bit downstream address format, but the processor never generates an address
above 64 GB (Bits 63:36 will always be zeros).
64-bit upstream address format, but the processor responds to upstream read
transactions to addresses above 64 GB (addresses where any of Bits 63:36 are
nonzero) with an Unsupported Request response. Upstream write transactions to
addresses above 64 GB will be dropped.
Supports the following traffic types to or from the PCH:
DMI -> DRAM
DMI -> processor core (Virtual Legacy Wires (VLWs), Resetwarn, or MSIs
only)
Processor core -> DMI
APIC and MSI interrupt messaging support:
Message Signaled Interrupt (MSI and MSI-X) messages
Downstream SMI, SCI and SERR error indication.
Legacy support for ISA regime protocol (PHOLD/PHOLDA) required for parallel port
DMA, floppy drive, and LPC bus masters.
DC coupling – no capacitors between the processor and the PCH.
Polarity inversion.
PCH end-to-end lane reversal across the link.
Supports Half Swing “low-power/low-voltage”.
DMI Error Flow
DMI can only generate SERR in response to errors, never SCI, SMI, MSI, PCI INT, or
GPE. Any DMI related SERR activity is associated with Device 0.
DMI Link Down
The DMI link going down is a fatal, unrecoverable error. If the DMI data link goes to
data link down, after the link was up, then the DMI link hangs the system by not
allowing the link to retrain to prevent data corruption. This link behavior 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 DMI link after a
link down event.
Interfaces—Processor
Desktop 4th Generation Intel
®
Core
Processor Family, Desktop Intel
®
Pentium
®
Processor Family, and Desktop Intel
®
Celeron
®
Processor Family
December 2013 Datasheet – Volume 1 of 2
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