Archive for November, 2015

From MCU or DSP to FPGA for Power Electronics: Part 2 Evaluation Boards and Hardware Issues

Thursday, November 26th, 2015

Migration from MCU or DSP to FPGA for Power Electronics

Following on from the first part of this post on migration from  MCU or DSP to FPGA for Power Electronics, the question was asked:

“…What suggestions do you have to start this migration, both in terms of a cheap evaluation board…”

This is a good question.  One of the first things you will need in starting an FPGA design is an evaluation board.  There are a large range of FPGA boards out there so here are a few suggestions:


Digilent Arty

Arty Board from Digilent


The Arty board, designed by Digilent and Avnet, is now one of the best and cheapest boards out there for starting out in FPGA designs.  For only $99US you get a moderately sized Xilinx Artix FPGA with a large range of peripherals.  It can be used for straight logic, or with a soft core Microblaze to act as a cheap SoC platform.  For more information on using the Arty, I would recommend Adam Taylor’s blog series here.  The Artix FPGA range is well suited to providing a more powerful system at a similar cost to some DSPs.


Zynq SoC Board on

Zed Board for Zynq


The Zedboard is almost the flagship evaluation board for the Zynq SoC.  Again from Digilent and Avnet, the Zedboard, with its powerful SoC and huge range of peripherals, has spawned a large community around it.  This evaluation board, although a bit more expensive than the Arty can pretty much do anything you need it to do.


Zed Board

Zed Baord


Although not necessarily a full board by itself, the Microzed is a Single Board Module (SBM) from Avnet.  With suitable base boards the Microzed becomes a powerful tool to use for development.  In some applications you can even use the Microzed in the final design.   Adam Taylor’s 100+ long blog post, the Microzed Chronicles, will allow you to get up to speed in no time with your new board.


One possible hurdle to using modern FPGAs is that they are all now in BGA packages.  Nigh on impossible to solder by hand and some lower end prototyping houses may not be able to handle them.  How do you get your design prototyped then?   The best option is to go for a SBM like the Microzed above or even one from Enclustra.   This changes the prototyping challenge from an impossible BGA to a much easier connector.  We at ELMG have used the Enclustra ones in the SODIMM form factor and the connectors are hand-solderable for rapid prototyping.

Contact Us

Feel free to contact Hamish to discuss your FPGA dreams and possible migration paths.


LinkedIn Group Digital Power Electronics Control now an open group

Monday, November 23rd, 2015

The LinkedIn Group Digital Power Electronics Control is now an open group.

That means that you can now join and then invite people to join.

Latest discussions in the group include how to get from C firmware to HDL and how to represent complex numbers in a DSP.

Join now.


Coffee Machine Upgrade – Full Steam Ahead

Thursday, November 19th, 2015

As mentioned in our previous post, sometimes with technology it is often the case that you simply need more power.  And so as we are coffee fans we decided that we needed more coffee power and got 6kW of it with a beautiful new machine.


Ready to fuel the development team

Ready to fuel the development team


UPDATE:  The machine is now on its shiny new table and making delicious coffees.  Come and visit and Tim will make you one.  You are welcome any time.



JTAG Boundary Scan Testing with AutoBuzz

Tuesday, November 17th, 2015

FPGAs have very large numbers of pins.  Ensuring that these are connected and are not shorted to each other requires electrical test vectors and sensing of shorts.

Boundary Scan

To run up FPGA PCBAs a great solution is boundary scan using a JTAG connection.  This lets you drive or sense, in turn, each and every pin on an FPGA or processor without having code loaded into the chip.

Continuity, possible shorted connections or pins stuck high or low can be detected very quickly.

Good low cost solution JTAG Live

We use a simple JTAG pod  to do JTAG Live FPGA Boundary Scan Testing.  It is really useful for PCBA run up and for short run production testing.


The video shows the use of the JTAG Live Autobuzz test function.  In this the AutoBuzz learns the connections on the board allowing rapid testing of connections.  It is a great first step in board run up.  Watch the video in full screen to see the detail.  Click the right bottom corner of the video to see it full screen.



Migration from MCU/DSP to FPGA for Power Electronics: Part 1 Software

Tuesday, November 17th, 2015

In a recent discussion we were asked about the migration path from MCU/DSP to FPGA.

“I am probably not alone when I use MCU/DSP devices to implement control algorithms, protection, logic etc to control the power hardware, using code such as ASM, C or C++, but want the advantages of FPGA. What suggestions do you have to start this migration, both in terms of a cheap evaluation board, and software tools, that can be targeted at driving various topologies and speeds.”

Thanks to Anthony W. for the question.  We get asked similar migration from MCU/DSP to FPGA for power electronics questions where the emphasis is more about retaining the value of an existing code base and coding team expertise while leveraging the flexibility of the FPGA.

As the first question states MCU/DSP devices are a common tool to implement control algorithms, protection, logic and sequencing for  control power hardware, using code such as ASM, C or C++.  However they do not have the power and flexibility of FPGAs. What is the best way to approach a migration from MCU/DSP to FPGA, both in terms of evaluation boards, and software tools, for a wide range of power electronic applications?

Best migration path MCU/DSP to FPGA for Power Electronics

There are a number of pathways to do this. The first one is High Level Synthesis. This is basically writing FPGA code in C. It is a very powerful tool but it does take some know how to make sure that you can get the most benefit out of the transition to FPGA. The downside of this is that it is quite expensive. There are however a couple of FPGA kits out there that do come with a kit-locked license (node-locked and locked to the FPGA model on the board).

Processor Inside

Another way is to use an FPGA with a processor, or processors, inside it. These processor can be soft-cores like Xilinx’s Microblaze or hard-cores like the twin ARM A9s in Xilinx’s Zynq series. (Reports on FPGA development projects show that almost 50% have some sort of processor.)  This processor allows you to directly port your code from your MCU/DSP to the Zynq/Microblaze and be ready to go. This may seem counter-productive as going from one processor to another without really gaining FPGA power is work for no reward.  The advantages come when you move parts of your code (the high intensity tasks such as the control algorithms) from C to the FPGA hardware. This provides a power boost for the important parts of your code whilst still having the simplicity of C for the easy flow of your code. A good analogy would be that the FPGA parts are the equivalent of the ASM parts on the MCU/DSP but with the superman type speed advantage of doing things in parallel in the FPGA fabric.

Best of both

Xilinx has also combined the HLS and the C coding options with their SDSoC product. It is designed for the Zynq SoC .  The coding is done in C. However you can use HLS to accelerate certain parts of the code for you to gain the most benefit.

Getting the most out of the Zynq solution does require either the expensive HLS toolchain and training in that or writing your own HDL. Another option is to purchase IP that other companies have written.  This allows you to create a fast and efficient system without needing to know coding of an FPGA in HDL or C.  ELMG Digital Power has a large suite of power electronics IP to get your application off the ground fast.

Prototyping and Development Platforms

In part 2 of this blog post, which is coming later, the answers to the questions

“How can I prototype this when the chip is BGA only?”


“What is an appropriate development platform or dev board?”

are covered.

Download the report ‘Your Digital Power Future – Roadblocks to Avoid’ to learn about the three key issues to watch out for in the Digital Control of Power electronics.

Download report now

Coffee Machine Upgrade

Monday, November 16th, 2015

Sometimes with technology it is often the case that you simply need more power.  And so as we are coffee fans we decided that we needed more coffee power. So we got a new machine.

And we were so keen to check it out that we had it hooked up and heating milk before the table for it had arrived.


Coffee Machine - FPGA and Power Electronics go better with good coffee.

Functional testing and verification of the new coffee machine.

Come visit us for a coffee.  You are welcome any time.