Category Archives: FPGA

Simulating the Learn-by-Fixing CPU

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Last time I looked at a simple 16-bit RISC processor aimed at students. It needed a little help on documentation and had a missing file, but I managed to get it to simulate using a free online tool called EDA Playground. This time, I’ll take you through the code details and how to run the simulation.

You’ll want to refer to the previous post if you didn’t read it already. The diagrams and tables give a high-level overview that will help you understand the files discussed in this post.

If you wanted to actually program this on a real FPGA, …read more

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A Full Stack GPS Receiver

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The usual way of adding GPS capabilities to a project is grabbing an off-the-shelf GPS module, plugging it into a UART, and reading the stream of NEMA sentences coming out of a serial port. Depending on how much you spend on a GPS module, this is fine: the best modules out there start up quickly, and a lot of them recognize the logical AND in ITAR regulations.

For [Mike], grabbing an off-the-shelf module is out of the question. He’s building his own GPS receiver from the ground up using a bit of hardware and FPGA hacking. Already he’s getting good …read more

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Phase Modulation With An FPGA

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There are two radio modulation schemes everyone should know. Amplitude modulation changes the amplitude — or ‘volume’, if you will — of a carrier frequency and turns all radio into channels owned and operated by a church. Frequency modulation changes the pitch of a carrier frequency and is completely run by Clear Channel. Amateur radio operators are familiar with dozens of other modulation schemes, but there’s one hardly anyone touches. Phase modulation is weird and almost unheard of, but that doesn’t mean you can’t implement it on an FPGA. [nckm] is transmitting audio using phase modulation on an FPGA  …read more

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Learn by Fixing: Another Verilog CPU

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Because I often work with students, I’m always on the look-out for a simple CPU, preferably in Verilog, in the Goldilocks zone. That is, not too easy and not too hard. I had high hopes for this 16-bit RISC processor presented by [fpga4student], but without some extra work, it probably isn’t usable for its intended purpose.

The CPU itself is pretty simple and fits on a fairly long web page. However, the details about it are a bit sparse. This isn’t always a bad thing. You can offer students too much help. Then again, you can also offer too little. …read more

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Learn by Fixing: Another Verilog CPU

Posted on by

Because I often work with students, I’m always on the look-out for a simple CPU, preferably in Verilog, in the Goldilocks zone. That is, not too easy and not too hard. I had high hopes for this 16-bit RISC processor presented by [fpga4student], but without some extra work, it probably isn’t usable for its intended purpose.

The CPU itself is pretty simple and fits on a fairly long web page. However, the details about it are a bit sparse. This isn’t always a bad thing. You can offer students too much help. Then again, you can also offer too little. …read more

Continue reading Learn by Fixing: Another Verilog CPU→

MATLAB and Simulink for Zynq

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Although we see a lot of MATLAB use in industry and in academia, it isn’t as popular in the hacker community. That’s probably due to the cost. If you’ve ever wondered why companies will pay over $2000 for the base product, you might enjoy the video of a webinar covering using MATLAB and Simulink (a companion product) to program the CPU and FPGA on a Zynq Zedboard. Not interested because of the price? If you aren’t using it for commercial purposes, it isn’t as bad as you think.

MathWorks is one of those companies that likes to market by virtually …read more

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FPGAs in C with Cynth

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Programming an FPGA with Verilog looks a lot like programming. But it isn’t, at least not in the traditional sense. There have been several systems that aim to take C code and convert it into a hardware description language. One of these, cynth, is simple to use and available on GitHub. You will need to install scala and a build system called sbt, if you want to try it.

There are limitations, of course. If you want a preprocessor, you’ll have to run it separately. You can’t use global variables, multiplication, floats, and many other pieces of C. The compiler …read more

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E-ink Display Driven DIY

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E-ink displays are awesome. Humans spent centuries reading non-backlit devices, and frankly it’s a lot easier on the eyes. But have you looked into driving one of these critters yourself? It’s a nightmare. So chapeau! to [Julien] for his FPGA-based implementation that not only uses our favorite open-source FPGA toolchain, and serves as an open reference implementation for anyone else who’s interested.

Getting just black and white on an E-ink display is relatively easy — just hit the ink pixels with the same signal over and over until they give up. Greyscale is made by applying much more nuanced voltages …read more

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Lattice iCE40 FPGA Configured by Linux Kernel

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The Linux kernel recently added support for loading firmware into an FPGA via the FPGA Manager Framework. [OpenTechLab] has built a driver for the Lattice iCE40 FPGA (same chip used on the iCEStick and other development boards). One attraction to the iCE40 is there is an open source toolchain called iCEStorm.

Even if you aren’t specifically interested in FPGAs, the discussion about Linux device drivers is good background. The principles would apply to other drivers, and would definitely apply if you want to write another FPGA loader.

The example uses a Raspberry Pi connected to an evaluation board. A cheap …read more

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Lattice iCE40 FPGA Configured by Linux Kernel

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The Linux kernel recently added support for loading firmware into an FPGA via the FPGA Manager Framework. [OpenTechLab] has built a driver for the Lattice iCE40 FPGA (same chip used on the iCEStick and other development boards). One attraction to the iCE40 is there is an open source toolchain called iCEStorm.

Even if you aren’t specifically interested in FPGAs, the discussion about Linux device drivers is good background. The principles would apply to other drivers, and would definitely apply if you want to write another FPGA loader.

The example uses a Raspberry Pi connected to an evaluation board. A cheap …read more

Continue reading Lattice iCE40 FPGA Configured by Linux Kernel→