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SPEC7

Featurealternatives

Last edited by Erik van der Bij
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SPEC7 Features

SPEC7 Features

  • 2-lane PCIe Gen2
    • Same 1 GByte/s total speed as 4-lane PCIe Gen1 on SPEC. Bridge integrated in FPGA
  • Xilinx Zynq FPGA with Dual-Core ARM processor integrated
    • XC7Z030-1FBG676C (~206 Euro) (-1= slowest, commercial temp range, fast enough for most applications?)
      • 4 GTX receivers (2 used for PCIe, 1 for SFP, 1 for FMC - same as on SPEC)
    • Possibility to mount Z035: XC7Z035-1FBG676C or XC7Z045-1FBG676C
      • 8 GTX receivers (2 used for PCIe, 1 for SFP, 3 for FMC, and 2 either for a) 4-lane PCIe or b) FMC)
      • FBG767 package has GTX tranceivers up to 6.6 Gb/s, FFG676 package enabled exploration of 10 Gb/s (see table 3 of Zynq-7000 SoC Data Sheet: Overview)
      • FBG676 package and FFG676 are footprint compatible (see note 1 on page 3 of zynq-7000-product-selection-guide)
  • FMC slot with high pin count (HPC) connector
    • Vadj fixed to 2.5V
    • Fully populated LA bank
      • All 34 differential pairs connected, 1 GTP transceiver with clock, 2 clock pairs, JTAG, I2C (as on SPEC)
    • Limited, partial connectivity of HPC part
      • xx signals on HA bank
      • DP1_M2C/C2M and DP2_M2C/2CM connected to two GTX transceivers only when Xilinx Z035 mounted
  • Clocking resources
    • 1x 10-280 MHz I2C Programmable XO Oscillator, starts up at 100 MHz (Silicon Labs Si570, freely usable)
    • 1x 125 MHz TCXO controlled by a DAC with SPI interface (used by White Rabbit PTP core) (Crystek CVPD-922 model)
    • 1x 124.992 MHz VCXO controlled by a DAC with SPI interface (used by White Rabbit PTP core) (Crystek CVPD-922 model)
  • On board memory
    • 1x 8 Gbit (1 GByte) DDR3 IC
    • 1x SPI xx Mbit flash PROM for multiboot FPGA powerup configuration, storage of the FPGA firmware
    • 64K (8K x 8-bit) I2C Serial EEPROM (24AA64T-I/MC) for storing serial number, calibration parameters and other critical data
    • Slot for flash memory for storing programs (MicroSD, UFS or MMC?)
  • 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, 2.5 and 10 Gbps
    • Programmable Red and Green LEDs
    • FMC front panel
  • Internal connectors
    • 1x JTAG header for Xilinx programming during debugging
    • 2x 14-pin header connector connected to GPIO, with ESD protection
    • 1x mini USB
      • Can serve two UARTs over the same single mini-USB connector with CP2105 - Dual UART bridge IC
    • Samtec Bulls-Eye connector (22 signals on the PCB, 6 cm2 land pattern, user mountable connector)
      • For PPS in/out, 10MHz in, tx-abscal, rx-abscal, refclock. 6 signals to be transferred in a differential way
  • FPGA configuration. The FPGA can optionally be programmed from:
    • JTAG header
    • SPI xx Mbit FLASH PROM
  • Stand-alone features
    • External 12V power supply connector
    • Mini USB connector
    • 4 LEDs
    • 2 buttons
  • Power consumption: 5-12 Watt, depending on application
  • Optimised for cost
    • 8-layer PCB
  • Optional cooling fan for the mezzanine

Functional differences with SPEC

Gained functionality

  • Larger, modern Zynq Z030 Xilinx with integrated Dual-Core ARM processor
  • More FPGA resources: Z-7030 vs XC6SLX45T: Logic cells: 125 K vs 44 K; CLB FF : 157 K vs 54 K (see selection guide)
  • Additional signals on FMC connector (partial HPC bank population)
  • Upgrade to Z035 and Z045 possible
    • Two or four extra GTX lines on FMC connector
    • Possibility of doubling PCIe bandwidth (2 GByte/s), but then only two extra GTX lines on FMC connector
  • Slot for flash memory (MicroSD, UFS or MMC?) for storing programs
  • Added 64K (8K x 8-bit) I2C Serial EEPROM (24AA64T-I/MC) for storing serial number, calibration parameters and other critical data separate from FPGA configuration
  • SFP+ at maximum 10 Gbps, instead of SFP at max 2.5 Gbps
  • 1 GB DDR3 instead of 256 MB
  • Dual UART on same mini-USB connector (e.g. for WR GUI and ARM processor)
  • Improved oscillators for lower jitter White Rabbit
  • Prepared for absolute calibration of White Rabbit
  • Prepared for installation of a cooling fan

Changed functionality

  • SATA connectors replaced by 14-pin headers. LVDS, GPIO connected, not to GTX anymore
  • PCB board size likely will be larger
  • Component price likely almost doubled

Cost of Alternatives

Existing SPEC: 180 Euro component cost (without PCB and front-panel) when bought in large quantities (several hundreds in one time).

  • Replacing Gennum: (57 Euro) and Spartan (40 Euro)

Alternative Xilinx Zynq series with ARM processor integrated:

  • Default: XC7Z030-1FBG676C (~206 Euro) (-1= slower, commercial temp range, will be fast enough for most applications?)
    • XC7Z030-2FBG676E (~285 Euro) (+79 Euro) (-2=faster, Extended temp range only, not available in commercial temp range)
  • Z035: 8 GTX receivers (4 used for PCIe, 1 for SFP, 1 for FMC - as on SPEC - and 2 for SATA). Makes it too expensive?
    • XC7Z035-2FBG676E (~1100 Euro) (-2=faster, Extended temp range only, not available in commercial temp range)
    • XC7Z035-1FBG676C (~800 Euro)

(Xilinx list prices compared for additional cost)

Total: with all options, 145 Euro extra cost (Xilinx, HPC, oscillators), total cost price 325 Euro. (cf. 180 SPEC). Prices without PCB and front-panel.
PCB will also be more expensive (likely larger, more layers). Memory cost also higher as 1GB instead of 256 MB.
Verify if possible to make low-cost version (cheaper oscillators, LPC with less layers)

Erik van der Bij, Peter Jansweijer - 24 October 2018