Open source FPGA toolchain builds CPU

August 18th, 2015

Ever wondered if you could run a J1a CPU on an FPGA using only open source hardware? This is possible using these three open source tools:

  • an Open Source Forth kernel, SwapForth
  • running on an Open Source CPU, the J1a
  • built using an entirely Open Source FPGA toolchain, IceStorm

When you develop software, you need some kind of toolchain. For example, to develop for an ARM processor, you need a suitable C compiler, a linker, a library, and a programmer. FPGAs use a similar set of tools. However, instead of converting source code to machine language, these tools map the intent of your source code into configuration of FPGA elements and the connections between them.


µGFX – embedded library for Displays and Touchscreens

July 30th, 2015

uGFXHere is an interesting GUI toolkit that we’d love to see running on the ZPUino!







µGFX is a library to interface all kinds of different displays and touchscreens to embedded devices. The main goal of the project is it to provide a set of feature rich tools like a complete GUI toolkit while keeping the system requirements at a minimum.

EEVblog #754 – Altium Circuit Maker First Impressions

July 28th, 2015

Altium’s free version of their PCB software called Circuit Maker is open to the public now. We gave it a spin and liked it, here is a video showing some more details.

Dave gives his first impression of Altium’s new FREE PCB design tool for the maker community, Circuit Maker.

Gates to FPGAs: TTL Electrical Properties

July 23rd, 2015

Great reference from Bil Herd about TTL Electrical properties.

On the path to exploring complex logic, let’s discuss the electrical properties that digital logic signals are comprised of. While there are many types of digital signals, here we are talking about the more common voltage based single-ended signals and not the dual-conductor based differential signals.

You can finally buy a Memristor!

July 21st, 2015

This is great news! Ever since first hearing about the memristor we have been wondering how long it will be before we see it show up in commercial applications. While 8 memristors for $249 is not very useful it is a very encouraging sign. Just imagine an FPGA made with memristors instead of transistors…

For the last few years, the people in the know have been wondering about the memristor. The simplest explanation of what a memristor is comes from the name itself – it’s a memory resistor. In practice it’s a little more complex, but this basic understanding is enough to convey the fact that it’s a resistor that changes its resistance based on how much current has gone through it. The memristor was first described in the 70s by [Leon Chua], the idea sat in journals for nearly forty years, and in 2008 a working memristor was created by HP Labs.

An Open Source Toolchain For iCE40 FPGAs

July 16th, 2015

This is a positive first step towards an open source toolchain for FPGA’s. Hopefully we will see something for Xilinx FPGA’s as well. We can always dream that Xilinx will open the format!

After months of work, and based on the previous work of [Clifford Wolf] and [Mathias Lasser], [Cotton Seed] has released a fully open source Verilog to bitstream development tool chain for the Lattice iCE40LP with support for more devices in the works.

Hacking the OV7670 camera module (SCCB cheat sheet inside)

June 25th, 2015

Here at Gadget Factory we’ve been thinking about the best way to provide support for the OV7670 Camera Wing that we have. This page we came across provides a treasure trove of information about how the OV7670 camera works.




The OV7670 is a low cost image sensor + DSP that can operate at a maximum of 30 fps and 640 x 480 (“VGA”) resolutions, equivalent to 0.3 Megapixels. The captured image can be pre-processed by the DSP before sending it out. This preprocessing can be configured via the Serial Camera Control Bus (SCCB). You can see the full datasheet here.