/-
These are the differential reference clock pair for the XMC 2 PCI Express interface. This differential
signal pair is generated by the VP3500 and transmitted to the mezzanine. This signal is required to be
provided for PCI Express add-in boards and is used to synchronize devices on both ends of a link. This
clock is 100MHz (+/- 300ppm) however please refer to the PCI Express Electromechanical Specification
for the detailed requirements of this signal.
An XMC may use CLK-REF to derive its on board PCI Express interface clocks although it is not
required.
TRST_L, TCK, TMS, TDI & TDO
XMC JTAG signals. XMC JTAG chain testing is not supported on the VP3500. TRST_L is connected to
ground, TCK, TMS & TDI are pulled up to +3.3V through 8.2K ohm resistors and TDO is not connected.
MBIST_L
XMC Built In Self Test. This signal allows the VP3500 to determine whether an XMC has completed its
built-in self test. If this signal is used, it shall be asserted low at the de-assertion of RESET_L to indicate
that the XMC is performing self-test and is not yet ready. This VP3500 input signal is pulled up to +3.3V
through an 8.2K ohm resistor and routed to microcontroller pin 54.
GA[2:0]
XMC I2C Geographical Address. These signals allow the VP3500 to address a specific XMC slot. The
XMC decodes these signals to determine its IPMI I2C address as shown in VITA specification 42.0, Table
5-2. The GA address for XMC slot 2 is 001.
NVMRO
Non Volatile Memory Read Only or XMC Write Prohibit. When this signal is asserted high, the XMC
shall disable writes to non-volatile memory on the XMC. This signal is an input to the XMC card and is
generated by a device on the VPX backplane.
WAKE_L
An open-drain, active low signal that is driven low by an XMC PCI Express function to reactivate the
links main power rails and reference clocks. The VP3500 does not support XMC power on/off control,
therefore, the WAKE function is routed to both XMCs and pulled up to +3.3V through an 8.2K resistor.
VP3500 User Manual • Document Number 101-3500-0001 • Revision A0
Property of Rigel Engineering, LLC. Confidential & Proprietary
690 Cone Park Court, Merritt Island, Florida 32952
page 44