10–4
Chapter 10: Optional Features
Lane Initialization and Reversal
Arria V GZ Hard IP for PCI Express
November 2012
Altera Corporation
Lane Initialization and Reversal
Connected components that include IP blocks for PCI Express need not support the
same number of lanes. The ×4 variations support initialization and operation with
components that have 1, 2, or 4 lanes. The ×8 variant supports initialization and
operation with components that have 1, 2, 4, or 8 lanes.
The Arria V GZ Hard IP for PCI Express supports lane reversal, which permits the
logical reversal of lane numbers for the ×1, ×2, ×4, and ×8 configurations. Lane
reversal allows more flexibility in board layout, reducing the number of signals that
must cross over each other when routing the PCB.
summarizes the lane assignments for normal configuration.
summarizes the lane assignments with lane reversal.
Yes
No
TD
=0, without ECRC
TD
=0, without ECRC
Core forwards the
ECRC
TD
=1, with ECRC
TD
=1, with ECRC
Yes
TD
=0, without ECRC
TD
=0, without ECRC
TD
=1, with ECRC
TD
=1, with ECRC
(1) All unspecified cases are unsupported and the behavior of the Hard IP is unknown.
(2) The
ECRC Generation Enable
field is in the
Configuration Space Advanced Error Capabilities and
Control Register
.
Table 10–3. ECRC Generation and Forwarding on TX Path
(1)
ECRC
Forwarding
ECRC
Generation
Enable
(2)
TLP on Application
TLP on Link
Comments
Table 10–4. Lane Assignments without Lane Reversal
Lane Number
7
6
5
4
3
2
1
0
×8 IP core
7
6
5
4
3
2
1
0
×4 IP core
—
—
—
—
3
2
1
0
×1 IP core
—
—
—
—
—
—
—
0
Table 10–5. Lane Assignments with Lane Reversal
Core Config
8
4
1
Slot Size
8
4
2
1
8
4
2
1
8
4
2
1
Lane
assignments
7:0,6:1,5:2,4:3,3:4,
2:5,1:6,0:7
3:4,2:5,
1:6,0:7
1:6,
0:7
0:7
7:0,6:1,
5:2,4:3
3:0,2:1,
1:2,0:3
3:0,
2:1
3:0
7:0
3:0
1:0
0:0