Kontron COMe Starterkit Eval T2 - Manual (Page 54)

COM Express Interfaces
Figure 19: PEG Lane Reversal Mode
To activate the Lane Reversal mode for the PEG Port, the COM Express specification defines an
active low signal 'PEG_LANE_RV#', which can be found on the Modules connector at row D pin
D54. This pin is strapped low on the Carrier Board to invoke Lane Reversal mode.
Note Please be aware that the SDVO lines on Type 2 Modules (Section 2.5.2) that share the PEG
Port (Section 2.4) may not support Lane Reversal mode. This is the reason that there are
“normal” (ADD2-N) and “reverse” (ADD2-R) pin-out ADD2 cards on the market. ADD2-N
cards are used in a PEG slot that does not employ lane reversal. An ADD2-R card is used
in a PEG slot that does employ lane reversal.
Check with your Module vendor to see if SDVO Lane Reversal is supported.
PICMG ® COM Express ® Carrier Board Design Guide Rev. 2.0 / December 6, 2013
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pin 1
COM Express
Module
(PEG_TX14+)
(PEG_TX14-)
(PEG_RX14+)
(PEG_RX14-)
(PEG_TX15+)
(PEG_TX15-)
(PEG_RX15+)
(PEG_RX15-)
(PEG_TX0+)
(PEG_TX0-)
(PEG_RX0+)
(PEG_RX0-)
(PEG_TX1+)
(PEG_TX1-)
(PEG_RX1+)
(PEG_RX1-)
Connectivity before Lane Reversal Connectivity after Lane Reversal
COM Express
Module
Carrier Board x16
PCIe Device
Carrier Board x16
PCIe Device
PEG_TX0+
PEG_TX14+
.
.
.
PEG_TX14-
PEG_RX14+
PEG_RX14-
PEG_TX15+
PEG_TX15-
PEG_RX15+
PEG_RX15-
PEG_TX0-
PEG_RX0+
PEG_RX0-
PEG_TX1+
PEG_TX1-
PEG_RX1+
PEG_RX1-
pin 1
PEG_TX0+
PEG_TX0-
PEG_RX0+
PEG_RX0-
PEG_TX1+
PEG_TX1-
PEG_RX1+
PEG_RX1-
PEG_TX14+
PEG_TX14-
PEG_RX14+
PEG_RX14-
PEG_TX15+
PEG_TX15-
PEG_RX15+
PEG_RX15-
.
.
.
PEG_TX0+
PEG_TX0-
PEG_RX0+
PEG_RX0-
PEG_TX1+
PEG_TX1-
PEG_RX1+
PEG_RX1-
PEG_TX14+
PEG_TX14-
PEG_RX14+
PEG_RX14-
PEG_TX15+
PEG_TX15-
PEG_RX15+
PEG_RX15-
.
.
.
PEG_TX0-
PEG_TX0+
PEG_RX0-
PEG_RX0+
PEG_TX1-
PEG_TX1+
PEG_RX1-
PEG_RX1+
PEG_TX14-
PEG_TX14+
PEG_RX14-
PEG_RX14+
PEG_TX15-
PEG_TX15+
PEG_RX15-
PEG_RX15+
.
.
.
pin 1
pin 1