Let's be honest... this is a page that has answers to the questions we think you should be asking.

What does "open standard" mean? 

While Opal Kelly owns and maintains the SYZYGY standard, the name and mark may be licensed for free by vendors to create carriers and peripherals compatible with the standard. By encouraging the proliferation of the standard, this openness is intended to grow the SYZYGY ecosystem to multiple vendors working together to increase customer value.

Why are standard and transceiver connectors different? 

All current and past generations of FPGAs differentiate standard I/O pins and transceiver-capable I/O pins at the package level. Therefore, there is no cross-compatibility advantage to using the same connector for both peripheral types. There are several advantages, however, including:

  • Lower standard connector cost
  • Lower cable cost for standard peripherals
  • Better pin count utilization for both types

What FPGAs are supported?

SYZYGY is FPGA-agnostic and is intended to work with products from all major FPGA manufactures including Xilinx, Intel, Lattice, and Microsemi.


SYZYGY DNA is an interface and protocol that provides a simple way for peripherals to communicate a few pieces of "personality" data to the carrier. It plays roughly the same role as the IPMI EEPROM in the VITA 57.1 (FMC) standard. This personality data includes:

  • SmartVIO - FPGA VIO operating voltage range
  • Manufacturer name
  • Product name
  • Serial number

Is the SYZYGY Hub Open Source? 

Yes. Upon release, we intend to release the SYZYGY schematics, PCB layout artwork, and firmware sources as a reference design for other vendors to develop SYZYGY compatible carriers and peripherals.

Have you heard of Digilent's PMOD? 

Yes! We love PMODs. In fact, Opal Kelly's own XEM6002 supports PMOD. Unfortunately, PMOD has some limitations that SYZYGY addresses such as:

  • Connectors unsuitable for some high-performance peripherals
  • Lack of impedance control

Low pin count unsuitable for some peripherals PMOD peripherals tend to be I2C, SPI, and other simple devices. PMOD and SYZYGY can happily coexist in the FPGA space and even on the same carrier implementations!

Have you heard of VITA 57.1 (FMC)? 

 Yes! We love FMC. In fact, Opal Kelly's own XEM6006 and XEM7350 support FMC. Unfortunately, FMC has some disadvantages that SYZYGY addresses such as:

  • Connectors are expensive and not "approachable" for some
  • FMC ports consume a LOT of FPGA pins

FMC peripherals tend to be very high performance devices and are often composite devices (multi-function) to make better use of the connector pins. FMC and SYZYGY can happily coexist in the FPGA space and even on the same carrier implementations!

© 2024 by Opal Kelly