SYSTEM OPERATION
4-2
PCIe2-2711 PCI Express Gen2 Expansion System User’s Manual
Revision 1.1, October 2017
4.3.3
PCIe-426 LED Indicators
The bottom (or left) LED on the front panel is the "Cable Present Detect" LED. This LED reflects the
status of the "CPRSNT#" signal in the PCIe Expansion Cable. When the LED is ON, it is indicating that
the "CPRSNT#" signal is asserted. The PCIe-460 chassis asserts "CPRSNT#" to indicate that it is
present, the cable is connected and power is good. If this LED is OFF, there may be a problem with
+3.3V power in the expansion chassis or the PCIe Expansion Cable is not connected properly.
The top (or right) LED on the panel is "Expansion System Signal Detect". The LED is on when the
PCIe-426 detects a signal on Lanes 0-3 of the PCIe cable. The LED ON indicates normal operation. If
the LED is not on, there is something wrong with the cable or the expansion system is not operating
properly.
4.3.4
PCIe-426 Output Swing, De-Emphasis and Receive Equalization
The transceiver silicon used on the PCIe-426 has eight steps of programmable de-emphasis, four steps
of output swing and eight steps of receive equalization. The PCIe-426 has three DIP switches to adjust
these settings on the cable interface. The as-shipped-default DIP switch configuration is what Cyclone
Microsystems has determined is the best setting for Gen1 or Gen2 operation with both the 1m and 3m
PCIe cables shipped with Cyclone PCIe Expansion systems. Users should not change the DIP switch
settings unless they have the proper test equipment to verify their results. Users change de-emphasis,
output swing and receive equalization at their own peril. The default DIP switch configuration is shown
below:
Table 4-1. PCIe-426 Default DIP Switch Configuration
4.4
PCIe-436 UPSTREAM CABLE ADAPTER
The cable interface for the expansion chassis is the PCIe-436 Upstream Cable Adapter. It is only
installed in slots J10 and J19of the PCIe-460.
4.4.1
PCIe-436 Power
The PCIe-436 only uses +3.3V power from the expansion chassis.
POSITION
SWITCH S1
SWITCH S2
SWITCH S3
1
OFF
OFF
ON
2
OFF
ON
ON
3
ON
ON
ON
4
ON
ON
OFF
