This article was originally published on March 23, 2020.
Editor’s Note: This content is contributed by Michael Zapke, Marketing Lead, Industrial.
Did Adam Taylor’s recent articles (Spartan-7 and the SP701 Board, SP701 environmental sensor application) make you curious about the new SP701 Evaluation Kit with a cost effective and very capable Spartan®-7 XC7S100 FPGA on it? Then you probably noticed that there are two Ethernet ports and wondered what you can do with board. Here’s an idea: Use it as an EtherCAT Slave!
Two triple-speed Ethernet ports connected to FPGA logic are ideal for implementing Industrial Ethernet with strict real-time requirements. EtherCAT is one of the most popular protocols for networks between industrial controllers, actuators like electric drives, sensors, and I/Os. EtherCAT slaves have support in hardware to treat traffic in a very deterministic manner, so that latencies are short and predictable and can cycle traffic in small intervals down to 12.5µs. Slaves can be realized with a dedicated ASIC, but often it is more attractive to fully integrate it in a platform device that also contains custom functions.
The EtherCAT Technology Group (ETG) is the point of contact for all companies who deploy EtherCAT and maintains and evolves the Framework for EtherCAT use. Xilinx is one of the over 5,700 members of the ETG. EtherCAT’s history is strongly linked with the company who invented EtherCAT: The automation technology specialist Beckhoff Automation from Germany. Beckhoff offers a wide range of EtherCAT products, which includes an EtherCAT IP core for FPGAs that ETG members can evaluate and license.
EtherCAT Slave, Now on SP701
SP701 now has a no-charge EtherCAT Slave example design that comes directly from Beckhoff. It contains:
- EtherCAT IP core for Vivado® IP integrator (IPI)
- A wrapper for use in an AXI and RGMII context
- A TCL script to build the design
- The EtherCAT device description in XML
- C sources as software templates for Xilinx SDK to create an example application
- Documentation (PDF) that describes the implementation of the example design and the functionality of the demo.
The configuration on the SP701 has two RGMIIs that use the onboard PHYs and RJ-45 ports. Functionally, 4 FMMUs, 4 SyncManagers, and distributed clock are supported. For the test application, a MicroBlaze™ soft core is part of the example design, which is connected through AXI4. This example design uses 23% of the slice LUTs, 54% of the block RAM, and 13% of the mixed mode clock managers (MMCMs) (1 out of and leaves lots of room for added custom function.
Spartan-7 FPGA for Cost-Optimized Connected Industrial Nodes
The Spartan-7 FPGA is an ideal device for flexible connectivity, sensor fusion, and embedded vision—with best-in-class performance per watt and small form factor packaging to meet the most stringent requirements.
Beckhoff’s EtherCAT slave IP core enables Spartan-7 FPGA to provide the following at a very optimized cost:
- motor controls
- smart sensors
- industrial I/Os
- machine vision
The programmable logic, high count of flexible I/Os up to 1.25Gb/s LVDS, and optional use of processor soft cores like MicroBlaze or Arm® Cortex®-M1 and -M3 build a complete EtherCAT capable node that can run stand-alone or connected to a host processor. The high amount of Pmod connectors enables an easy and cost-efficient extension with commercial modules.
Get Your License for EtherCAT!
IP licenses are available from Beckhoff automation. If you are not a member of the EtherCAT technology group yet, then please request your free membership. Find details on ETG’s homepage: ethercat.org.
For members, a 3-month node-locked evaluation license EtherCAT IP core can be requested at Beckhoff at no charge. You’ll also get access to the SP701 example design there.
Beckhoff’s full EtherCAT IP Core for Xilinx can also be licensed for product development under the order codes ET1815 and ET1816. Reach out to your nearest Beckhoff sales office or send michael.zapke@xilinx.com an email for details.