Open source Linux-on-Zynq SBC debuts new FPGA add-on standard
Nov 22, 2017 — by Eric Brown 2,942 viewsOpal Kelly’s “SYZYGY Brain-1” SBC, which runs Linux on a Zynq-7012S, is a proof of concept for its SYZYGY standard for FPGA-driven peripherals.
FPGA development firm Opal Kelly has gone to Crowd Supply to launch a development board to showcase its SYZYGY standard for FPGA peripheral expansion. SYZYGY bridges the gap between Digilent’s low-speed Pmod connector and the higher-end VITA 57.1 FMC (FPGA Mezzanine Card) standard. The open source, 110 x 75mm SYZYGY Brain-1 SBC runs Linux on a Xilinx Zynq-7012S SoC, a member of the FPGA-enabled Zynq-7000S family, which offers single Cortex-A9 cores instead of the dual cores on the Zynq-7000 series.


SYZYGY Brain-1 (left) and with connected SYZYGY modules
(click images to enlarge)
The $325 SYZYGY Brain-1 board will ship to backers on Feb. 5 along with 5x optional SYZYGY daughter-boards, up to 4x of which can be connected simultaneously. These include a $40 POD-PMOD4 (Pmod) board, a $70 $100+ DAC, a $70 POD-DUALSFP (for fiber optic SFP gigabit transceivers), a POD-DAC-AD9116 (DAC), a $120 POD-ADC-LTC2264-12 (ADC), and a $150 POD-CAMERA (3.4-megaxpixel) board. After the campaign, Opal Kelly plans to produce another six boards, including breakout, sensors, microphone array, robotics motor and servos, AV with HDMI and audio, and GSPS data acquisition (see full listings farther below).
SYZYGY standard
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Opal Kelly, which is known for its USB and PCIe modules designed for FPGA systems, announced the open SYZYGY standard in August. The standard fills the gap between the two major FPGA expansion standards. Digilent’s Pmod has 6-and 12-pin connectors designed for an up to 50MHz range. The FMC standard requires expensive 72-pin and 200-pin connectors for communicating with similarly pricey expansion boards at up to 10Gbps data rates.


SYZYGY comparative diagram (left) and chart
(click images to enlarge; source: Opal Kelly)
SYZYGY offers Standard and Transceiver connector types, both of which use Samtec connectors. The 40-pin Standard connector supports up to 28 single-ended, impedance-controlled signals at up to 500MHz per pin, while the higher-speed, 60-pin Transceiver connector has up to 16 single-end signals at up to 200MHz and up to 8x Gigabit transceiver pins at up to 5GHz per pin. According to an Embedded report on SYZYGY, the Transceiver connector is “intended for use with JESD204B data acquisition, SFP+ transceivers, and other devices requiring high-speed SERDES.”


SYZYGY modules currently available (left) and planned
(click images to enlarge; source: Opal Kelly)
Both the Standard and Transceiver connectors can be connected directly to the onboard connectors or via optional coaxial or twin-axial cable assemblies. Campaign pricing for the 6-inch coaxial Standard cable and twin-axial Transceiver cables are $30 and $60, respectively. Typical low-volume pricing is under $45 for Standard coaxial and under $90 for Transceiver twin-axial. High-volume pricing is $19 or $38.
The SYZYGY connectors are supported with SYZYGY DNA and SmartVIO communications firmware. The DNA firmware communicates personality data from the cards to the mainboard including manufacturer, product, and serial number. SmartVIO defines the range of acceptable I/O voltages.
Inside the SYZYGY Brain-1
The $325 price for the SYZYGY Brain-1 includes 1GB DDR3 RAM, an 8GB microSD card, and a 12V, 3A power supply. The board supports a wide 5-18V input, which is one of several advantages cited over most of the other Zynq-based SBCs listed in Opal Kelly’s comparative mini feature table. These include the Trenz TE0715-04-12S, the PicoZed 7015, and the Snickerdoodle Black.


SYZYGY Brain-1 with first five modules (left) and angled photo
(click images to enlarge)
Other claimed SYZYGY Brain-1 advantages over its listed rivals include standard GbE and USB ports (OTG Type-C and USB serial console) without requiring a breakout board, as well as standard 8x LEDs and 2x pushbuttons. The main advantage, however, is the new class of peripherals enabled by its middle-of-the-road SYZYGY standard, says Opal Kelly.

SYZYGY Brain-1 block diagram
(click image to enlarge)
The SBC and SYZYGY daughter-boards ship with schematics and PCB artwork for open source experimentation. There’s also a free Linux BSP with source code.
Specifications listed for the SYZYGY Brain-1 SBC include:
- Processor — Xilinx Zynq-7012S — 1x Cortex-A9 @ 667MHz with FPGA (55k logic cells, 2.5Mb block memory, 120 DSP slices); optional dual-core Zynq-7015 with 74k logic cells, 160 DSP slices, 4x 6.25Gbps transceivers
- Memory/storage — 1GB DDR3 RAM; microSD slot
- Networking — Gigabit Ethernet port
- Other I/O:
- USB OTG Type C port
- USB-based serial console port
- JTAG interface
- Expansion:
- 3x Standard SYZYGY — 28x I/Os each; 2x clock pairs each (can be used as I/O)
- 1x Transceiver port — 18x I/Os; 2x GTP receive pairs and 2x GTP transmit pairs (both up to 3.75Gbps); 1x transceiver reference clock pair
- Other features – 8x LEDs; 2x user I/O buttons; reset button; optional peripheral mounting hardware; optional 6-inch multi-conductor peripheral cabling
- Power — 5-18V DC; 12V, 3A power supply
- Dimensions — 110 x 75mm
- Operating system — Linux
Further information
The SYZYGY Brain-1 is available through Jan. 9 on Crowd Supply starting at $325 (see peripheral and cable prices above). More information may be found on the SYZYGY Brain-1 Crowd Supply page and Opal Kelly website, as well as Opal Kelly’s SYZYGY website.
Isn’t this a tad expensive, given that Parallel w/ Zynq7010 or w/ Zynq7020 can be had for $125 or for $160, respectively?
@blu – depends on the application. Parallella 7010 / 7020 don’t have transceiver-capable FPGAs and don’t have power supplies for expansion devices. AFAICS the Parallella don’t have expansion connectors populated either. So it’s not an apples-to-apples comparison. If you just want the processor, the Brain-1 isn’t your best option.
@Jake, thank you for the clarification. I was really puzzled by the price disparity.