12th Generation Intel® Core™ Processors Datasheet, Volume 1 of 2

Datasheet

ID 655258
Date 28/10/2021 00:00:00
Public Content

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Document Table of Contents

PCI Express* Support

The S-processor PCI Express* has two interfaces:

  • 16-lane (x16) port supporting PCIE to gen 5.0 or below that can also be configured as multiple ports at narrower widths.
  • 4-lane (x4) port supporting PCIE gen 4.0 or below.

The processor supports the following:

  • Hierarchical PCI-compliant configuration mechanism for downstream devices.
  • Traditional PCI style traffic (asynchronous snooped, PCI ordering).
  • PCI Express* extended configuration space. The first 256 bytes of configuration space aliases directly to the PCI Compatibility configuration space. The remaining portion of the fixed 4-KB block of memory-mapped space above that (starting at 100h) is known as extended configuration space.
  • PCI Express* Enhanced Access Mechanism. Accessing the device configuration space in a flat memory-mapped fashion.
  • Automatic discovery, negotiation, and training of link out of reset.
  • Multiple Virtual Channel for Gen 4 port only*.
  • 64-bit downstream address format, but the processor never generates an address above 4096 GB (Bits 63:43 will always be zeros).
  • 64-bit upstream address format, but the processor responds to upstream read transactions to addresses above 4096 GB (addresses where any of Bits 63:43 are nonzero) with an Unsupported Request response. Upstream write transactions to addresses above 4096 GB will be dropped.
  • Re-issues Configuration cycles that have been previously completed with the Configuration Retry status.
  • PCI Express* reference clock is a 100-MHz differential clock.
  • Power Management Event (PME) functions.
  • Modern standby
  • Dynamic width capability.
  • Message Signaled Interrupt (MSI and MSI-X) messages.
  • Lane reversal
  • Advanced Error Reporting (AER)
  • MCTP VDM tunneling.
  • ACS - Access control services
  • Hotplug is supported on PEG60/62 only. It is not supported on PEG10/11
  • Precision Time Management (PTM) - This feature is supported on PEG60/62 with the exception of ECN for byte ordering of the PTM value not being supported. PEG10/11 do support ECN for byte ordering

The S processor supports the configurations shown in the following tables:

PCI Express* 16 - Lane Bifurcation and Lane Reversal Mapping

Bifurcation Link Width CFG Signals Lanes
0:1:0 0:1:1

CFG

[6]

CFG

[5]

CFG

[2]

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
PCIe controller PCIe 010
1x16 x16 N/A 1 1 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1x16

Reversed

x16 N/A 1 1 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
PCIe controller PCIe 010 PCIe 011
2x8 x8 x8 1 0 1 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
PCIe controller PCIe 011 PCIe 010
2x8

Reversed

x8 x8 1 0 0 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
Notes:
  1. For CFG bus details, refer to Reset and Miscellaneous Signals.
  2. Support is also provided for narrow width and use devices with lower number of lanes (that is, usage on x4 configuration), however further bifurcation is not supported.
  3. In case that more than one device is connected, the device with the highest lane count, should always be connected to the lower lanes, as follows:
    1. Connect lane 0 of 1st device to lane 0.
    2. Connect lane 0 of 2nd device to lane 8.
  4. For reversal lanes, for example: When using 1x8, the 8 lane device should use lanes 8:15, so lane 15 will be connected to lane 0 of the Device.

S- Processor PCI Express* 4 - Lane Reversal Mapping

Bifurcation

Link Width

CFG Signals

Lanes

0:6:0

CFG [14]

0

1

2

3

PCIe controller PCIe 060

1x4

x4

1

0

1

2

3

1x4 Reversed

x4

0

3

2

1

0

Note:PCIe* Port60 is a single x4 port without bifurcation capabilities, thus bifurcation pin straps are not applicable.

PCI Express* Maximum Transfer Rates and Theoretical Bandwidth

PCI Express* Generation

Encoding

Maximum Transfer Rate

[GT/s]

Theoretical Bandwidth [GB/s]

S

x4

S

x8

S

x16

Gen 1

8b/10b

2.5

1.0

2.0

4.0

Gen 2

8b/10b

5

2.0

4.0

8.0

Gen 3

128b/130b

8

3.9

7.9

15.8

Gen 4

128b/130b

16

7.9

15.8

31.5

Gen 5

128b/130b

321

15.81

31.51

631

Note:1. Transfer rate and max theoretical Bandwidth are not final and could be lowered.

The above table summarizes the transfer rates and theoretical bandwidth of PCI Express* link.