One Clock Cycle Polynomial Math
Error correction codes and cryptographic computations are most easily performed working with $GF(2^n)$ polynomials. By using very special values of $n$ we can build circuits which multiply and square in one clock cycle on an FPGA. These circuits come about by flipping back and forth between a standard polynomial basis and a normal basis representation of elements in $GF(2^n)$.
A normal basis is yet another form of polynomial but instead of adding powers of $\beta$ we add...
Elliptic Curve Cryptography
Secure online communications require encryption. One standard is AES (Advanced Encryption Standard) from NIST. But for this to work, both sides need the same key for encryption and decryption. This is called Private Key encryption. Public Key encryption is used to create a private key between two sides that have not previously communicated. Compared to the history of encryption, Public Key methods are very recent having been started in the 1970's. Elliptic...
An absolute position encoder VHDL core
Introduction
Let's consider motorized systems controlled by electronics. A closed loop architecture looks like this:
The following components are involved:
- the motor itself (DC, stepper ...),
- the controller, in charge of computing position according to the whole system state,
- the driver board in charge of generating signals and power for the motor,
- the position encoder, the subject of this post.
Most of the time, there is a difference between the position the system...
Helping New Bloggers to Break the Ice: A New Ipad Pro for the Author with the Best Article!
Breaking the ice can be tough. Over the years, many individuals have asked to be given access to the blogging interface only to never post an article. Maybe they underestimated the time it takes to write a decent article, or maybe they got cold feet. I don't blame or judge them at all - how many times in my life have I had the intention to do something but didn't follow through? Once, maybe twice 😉 (don't worry if you don't...
Polynomial Math
Elliptic Curve Cryptography is used as a public key infrastructure to secure credit cards, phones and communications links. All these devices use either FPGA's or embedded microprocessors to compute the algorithms that make the mathematics work. While the math is not hard, it can be confusing the first time you see it. This blog is an introduction to the operations of squaring and computing an inverse over a finite field which are used in computing Elliptic Curve arithmetic. ...
Welcoming MANY New Bloggers!
The response to the latest call for bloggers has been amazing and I am very grateful.
In this post I present to you the individuals who, so far (I am still receiving applications at an impressive rate and will update this page as more bloggers are added), have been given access to the blogging interface. I am very pleased with the positive response and I think the near future will see the publication of many great articles, given the quality of the...
Recruiting New Bloggers!
Previous calls for bloggers have been very successful in recruiting some great communicators - Rick Lyons, Jason Sachs, Victor Yurkovsky, Mike Silva, Markus Nentwig, Gene Breniman, Stephen Friederichs,
Summer of Gateware
This (last) summer the MyHDL project participated in the Google Summer of Code (GSoC) as a sub-organization under the Python Software Foundation (PSF). This was our first year participating - there was a lot for us to learn. Overall it was a worthwhile and beneficial activity.
Being a first time sub-org we were limited to a maximum of two students. We had nine students apply and twelve mentors volunteer. Only being able to select two students...
Tools of the Trade: reading PDFs (and keeping bookmarks)
In this article I will take a look at the wonderful MuPDF viewer and present a small modification that saves bookmarks alongside the pdf files, making it infinitely more useful.
Some days I sit down to work and wonder how anything ever gets done. A simple example. When I work on an FPGA design, I wind up with 3 or 4 screens full of documentation, generally in PDF format. There are the Xilinx manuals, the various tool manuals, language reference manuals, you name it. While...
Inside the Spartan-6: Using LUTs to optimize circuits
While building a small CPU on a Spartan-6 chip I came across the same old problem: my Verilog was mapping to a lot of slices . Way more then seems reasonable. So let's dig in and see what's really going on.
The J1 CPU (see Messing Around with a J1) is an amazingly streamlined design expressed in just over 100 lines of Verilog, and is reasonably compact at 150 Spartan-6 slices (half of that with the modifications described in the article). But the Picoblaze is...
Data Types for Control & DSP
There's a lot of information out there on what data types to use for digital signal processing, but there's also a lot of confusion, so the topic bears repeating.
I recently posted an entry on PID control. In that article I glossed over the data types used by showing "double" in all of my example code. Numerically, this should work for most control problems, but it can be an extravagant use of processor resources. There ought to be a better way to determine what precision you need...
An absolute position encoder VHDL core
IntroductionLet's consider motorized systems controlled by electronics. A closed loop architecture looks like this:
The following components are involved:
- the motor itself (DC, stepper ...),
- the controller, in charge of computing position according to the whole system state,
- the driver board in charge of generating signals and power for the motor,
- the position encoder, the subject of this post.
Most of the time, there is a difference between the position the system...
StrangeCPU #1. A new CPU
Summary: In this multi-part series I will share with you a design, implementation notes and code for a slightly different kind of a CPU featuring a novel token machine that resolves an 8-bit token to pretty much any address in a 32-bit or even 64-bit address space, using not much more than an adder.
Table of Contents:- Part 1: A new CPU - technology review, re-examination of the premises; StrangeCPU concepts; x86 notes.
Feedback Controllers - Making Hardware with Firmware. Part 9. Closing the low-latency loop
It's time to put together the DSP and feedback control sciences, the evaluation electronics, the Intel Cyclone floating-point FPGA algorithms and the built-in control loop test-bed and evaluate some example designs. We will be counting the nanoseconds and looking for textbook performance in the creation of emulated hardware circuits. Along the way, there is a printed circuit board (PCB) issue to solve using DSP.
Fig 1. The evaluation platform
Additional design...
Choosing an Implementation Approach
What one man can do, another can do!--The Edge (1997) Choose the hill you want to die on.--Common saying attributed to the United States Marine Corps Planning out an FPGA Implementation
In my first article, I gave a high-level view of the project that brings me into the world of FPGA development. At the end, I tried to break down the areas of development that would be involved, and some of the knowledge and expertise I would probably have to gain in order to make it a...
Embedded World 2018 - The Interviews
Once again this year, I had the chance to go to Embedded World in Nuremberg Germany. And once again this year, I brought my video equipment to try and capture some of the most interesting things at the show.
Something new this year, I asked Jacob Beningo if he would partner with me in doing interviews with a few vendors. I would operate the camera while Jacob would ask the right questions to the vendors to make them talk about the key products/features that...
Feedback Controllers - Making Hardware with Firmware. Part 5. Some FPGA Aspects.
This part of the on-going series of articles looks at a variety of aspects concerning the FPGA device which provides the high-speed maths capability for the low-latency controller and the arbitrary circuit generator application. In due course a complete specification along with application examples will be maintained on the project website here.- Part 5: Some FPGA Aspects (this part)
- Part 4: Engineering of...
MyHDL FPGA Tutorial II cont. (Echo, Audio Interface)
IntroductionTo demonstrate the echo on an FPGA board an interface to an audio ADC/DAC chip will be used. The following will explain the connection to the audio codec and the HDL module used to interface.
Audio Codec InterfaceI have two boards with TI AIC23b audio codecs. The AIC23 has a configuration interface (ability to program the registers) and a streaming audio interface. The SPI mode will be used to configure the codec and the I2S interface is used to send and...
Feedback Controllers - Making Hardware with Firmware. Part 8. Control Loop Test-bed
This part in the series will consider the signals, measurements, analyses and configurations for testing high-speed low-latency feedback loops and their controllers. Along with basic test signals, a versatile IFFT signal generation scheme will be discussed and implemented. A simple controller under test will be constructed to demonstrate the analysis principles in preparation for the design and evaluation of specific controllers and closed-loop applications.
Additional design...Fit Sixteen (or more) Asynchronous Serial Receivers into the Area of a Standard UART Receiver
Introduction
This article will describe a technique, available in many current FPGA architectures, to fit a large amount of logic into a small area. About ten years ago now (Feb/Mar 2005), I helped develop a multi-line Caller ID product. The Multi-Channel Asynchronous Receiver (MCAR) FPGA core developed for that product will be used to illustrate the technique(s) needed to fit a 16 channel MCAR into a single Spartan II XC2S30-5VQ100 FPGA.
To stay true to the original design, I...
MyHDL Resources and Projects
Last updated 07-Nov-2017
MyHDL ResourcesIf you want to dive into MyHDL (digital hardware description in Python) there are many resources available. Below is a list of MyHDL resources, including some of the past blogs here on fpgarelated.
The MyHDL manual is a great (probably the best) place to get started.
The manual is an in-depth introduction to MyHDL. The concepts are well explained and there are examples to test while working through the...
Crowdfunding Articles?
Many of you have the knowledge and talent to write technical articles that would benefit the EE community. What is missing for most of you though, and very understandably so, is the time and motivation to do it.
But what if you could make some money to compensate for your time spent on writing the article(s)? Would some of you find the motivation and make the time?
I am thinking of implementing a system/mechanism that would allow the EE community to...
Makefiles for Xilinx Tools
Building a bitstream from an HDL is a complicated process that requires the cooperation of a lot of tools. You can hide behind an IDE or grow a pair and use command line tools and a makefile to tie your build process together. I am not a huge fan of makefiles either (I believe a language should be expressive enough to automate the build process), but the alternatives are dismal.
Command-line driven workflow is easier on the hands and faster. The example...
FPGA Assemblers and Time Machines
Flashback to 1986. A young man has a crazy idea - he wants to make a CPU all by himself. He is reading early Xilinx manuals cover to cover as if they were novels. Yes, you are quick - this is indeed a (mostly) true story about me and my dream, suddenly made possible by this new FPGA technology.
Sadly more than 20 years went by before my first CPU ran in a Xilinx FPGA. Why did it take so long? Every few years I set up the tools and every time I walked away, scared silly. As the years...
Back from Embedded World 2019 - Funny Stories and Live-Streaming Woes
When the idea of live-streaming parts of Embedded World came to me, I got so excited that I knew I had to make it happen. I perceived the opportunity as a win-win-win-win.
- win #1 - Engineers who could not make it to Embedded World would be able to sample the huge event,
- win #2 - The organisation behind EW would benefit from the extra exposure
- win #3 - Lecturers and vendors who would be live-streamed would reach a (much) larger audience
- win #4 - I would get...
Back from ESC Boston
NOT going to ESC Boston would have allowed me to stay home, in my comfort zone.
NOT going to ESC Boston would have saved me from driving in the absolutely horrible & stressful Boston traffic1.
NOT going to ESC Boston would have saved me from having to go through a full search & questioning session at the Canada Customs on my return2.
2017/06/06 update: Videos are now up!So two days...
Data Types for Control & DSP
There's a lot of information out there on what data types to use for digital signal processing, but there's also a lot of confusion, so the topic bears repeating.
I recently posted an entry on PID control. In that article I glossed over the data types used by showing "double" in all of my example code. Numerically, this should work for most control problems, but it can be an extravagant use of processor resources. There ought to be a better way to determine what precision you need...
binary hello world
Python + Ohio + MyHDL + FPGARecently I had the opportunity to coordinate a hands-on programmable hardware (FPGA) workshop (open-space) at a regional Python conference - @pyohio. The workshop was for those that had little to no exposure to programmable hardware. For this situation I used two basic examples: two versions of a binary hello world.
The binary hello world -- blinking an LED -- is a good starting point to introduce programmable hardware, hardware descriptions languages,...
SEGGER's 25th Anniversary Video
Chances are you will find this video more interesting to watch if you take five minutes to first read the story of the week I spent at SEGGER's headquarters at the end of June.
The video is only a little more than 2 minutes long. If you decide to watch it, make sure to go full screen and I would really love to read your thoughts about it in the comments down bellow. Do you think a video like this succeeds in making the viewer want to learn more about the company?...
Running Average
The running average filter is a useful way to reduce noise in a system. One project I recently worked on required a 4 times frequency output from an encoder input. The problem was the encoder is mounted to the wheel of an old truck and bearing noise was making the original algorithm generate way too many pulses. The original algorithm worked, but the noise on the input made it useless.
I first implemented the moving average based on
