Simple PXI express FMC Carrier Board (SPEXI)

Project description

The PXI express FMC Carrier Board (SPEXI) is the PXI express version of the SPEC board. It is an FMC carrier that can hold one FMC card and an SFP connector. On the PXI express side it has a 4-lane interface, while the FMC mezzanine slot uses a low-pin count connector. This board will be usable with most of the FMC cards designed within CERN’s OHR project (e.g. ADC cards, Fine Delay).

LabVIEW drivers are available for the FMC DEL 1ns 4cha delay and FMC TDC 1ns 5cha TDC mezzanine cards.

Spexi means "I observe, watch, look at." in Latin.

SPEXI v1 production

Main Features

  • 4-lane PCIe (Gennum GN4124) obsolete component, not available anymore
  • 1x Xilinx Spartan6 FPGA (XC6SLX150T-3FGG900C)
  • FMC slot with low pin count (LPC) connector
    • Vadj fixed to 2.5V
    • FMC connectivity: all 34 differential pairs connected, 1 GTP transceiver with clock, 2 clock pairs, JTAG
    • No dedicated clock signals from Carrier to FMC (only available on HPC pins)
  • Simple clocking resources
    • 1x 10-280 MHz I2C Programmable XO Oscillator (Silicon Labs Si570)
    • 1x 25 MHz TCXO controlled by a DAC with SPI interface (AD5662, used by White Rabbit PTP core)
    • 1x 20 MHz VCXO controlled by a DAC with SPI interface (AD5662, used by White Rabbit PTP core)
    • 1x low-jitter frequency synthesizer (TI CDCM61004, fixed configuration, Fout=125MHz, used by White Rabbit PTP core)
  • On board memory
    • 1x 2Gbit (256 MByte) DDR3 (MT41J128M16JT-125)
    • 1x SPI 32Mbit flash PROM for multiboot FPGA powerup configuration, storage of the FPGA firmware or of critical data (M25P128-VMF6G)
  • Miscellaneous
    • on-board thermometer IC (DS18B20U+)
    • unique 64-bit identifier (DS18B20U+)
  • Front panel containing
    • 1x Small Formfactor Pluggable (SFP) cage for fibre-optic transceiver (WhiteRabbit support). 1.25 and 2.5 Gbps.
    • Programmable Red and Green LEDs
    • FMC front panel
  • Internal connectors
    • 1x JTAG header for Xilinx programming during debugging
    • 1x mini USB AB (USB-UART bridge)
  • FPGA configuration. The FPGA can optionally be programmed from:
    • GN4124 SPRIO interface (loaded by software driver at startup)
    • JTAG header
    • SPI 32Mbit flash PROM
    • selectable by GN4124 GPIO. Default option would be loading via the SPI flash PROM (stand-alone applications).
  • Debugging features
    • mini USB connector
    • 4 LEDs
    • 2 buttons
  • Optimised for cost
    • 8-layer PCB

PXIe specific features

  • PXI express form factor, 3U high, single slot
  • Clock and synchronisation back plane signals
PXI clock and synchronisation signals PXI express clock and synchronisation signals

Project information

Since the SPEXI is a board which is based on the design of the SPEC, some of the documentation of the SPEC can also be used.



FPGA examples (including the .ucf-file)

    The file contains a demo design and all the files including the .bit and .msc files which can be used to download this design to the SPEXI using Xilinx iMPACT and the download cable, or use the download path via the Gennum GN4124. This design contains the interface to the Gennum GN4124, an I2C master to access the FMC board eeprom, a carrier control and status register to get some information of the SPEXI carrier, and a GPIO register to access the four LEDs and the two buttons.
    To download the .mcs file into the SPI memory (M25P128) you will need to configure iMPACT to access the SPI flash memory connector to the Spartan-6 150T.
    The file contains the same design as but does not contain the GPIO register for the LEDs and buttons. This design is used to be able to get the first information from the SPEXI and the FMC to be able to determine which other FMC specific FPGA design could be loaded safely.
    The file contains the complete set of VHDL/FPGA designs and corresponding phyton files for the Production Test Suite. This PTS is used to test the boards functionally after manufacturing. Because of this the designs also contain several examples of how to connect to the other interfaces on the SPEXI carrier.


Commercial producers

General question about project


Date Event
06-04-2011 First ideas for project.
17-01-2012 Price Enquiry sent out for design by industry based on SPEC board.
12-03-2012 Order for design and two pre-series boards placed with INCAA. Delivery by 12-07-2012.
16-05-2012 Schematics being made.
29-05-2012 Removed SATA connectors and stand-alone possibility from specification.
17-08-2012 V0 Schematics and PCB uploaded and available for review
30-08-2012 First review V0 Review20120830.
04-10-2012 Second schematics review V0.
19-11-2012 V0-2 ready for review.
07-11-2012 V0-2 reviewed. Only one single minor comment.
21-01-2013 Bare PCBs ready for assembly of components.
07-02-2013 PCBs should be assembled by 22 February 2013.
07-03-2013 Assembled PCB available. Production Test Software being written based on SVEC PTS.
28-06-2013 V1-0 files being finalised. Ready in a week.
02-07-2013 V1-0 files ready for verification and cleanup by CERN design office.
30-07-2013 V1-0 files reviewed. Main comments about component spacing. Will clean up design.
28-08-2013 Added PROM to design and cleaned up files. Will be checked by CERN design office. Ordered 10 boards.
03-09-2012 Prototype SPEXI board received (from base layout).
25-09-2013 Design V1-0 checked and improved. Released for production.
08-10-2013 Driver Fine Delay card ported from SPEC to SPEXI. Ready for testing. TDC driver will be ported next.
03-12-2013 Labview Driver available for FMC DEL 1ns 4cha and FMC TDC 1ns 5cha.
30-01-2014 Series production of 10 cards received at CERN.
30-04-2014 Ordered 25 boards.
04-06-2014 Airbus Defence&Space: Evaluating SPEXI for use as backbone for future test systems for space electronics.
23-07-2014 Astrium GmbH, Germany, will use the SPEXI with the 24 bit ADC for measurements using PT1000.
31-07-2014 Received the 25 boards.
04-09-2015 4 SPEXI boards with FMC-DEL cards have been deployed in the kicker control systems at CERN (LEIR and others).
08-09-2015 A SPEXI boards with a FMC-TDC card is under study to be used.
22-04-2016 Airbus Defence&Space is using the SPEXI as their backbone in test systems for space electronics.
03-10-2016 The Ecole d'Ingénieurs in Fribourg will use the SPEXI
29-03-2017 In SM18 the SPEXI will be used with a TDC for magnet quench trigger time stamping

Erik van der Bij, Adriaan Rijllart - 31 March 2017