11 February 2021

Hello Nexys - Part 2

Welcome back to our three-part FPGA tutorial with SystemVerilog and the Digilent Nexys Video. In part two, we’re going to learn about clocks and counting. Along the way, we’ll cover maintaining state with flip-flops, timing things with clock dividers, creating our first Verilog module, and controlling LEDs with pulse width modulation. This post is also available for the Arty. This post was last updated in December 2021. New to the series? Read more

28 January 2021

Lines and Triangles

Welcome back to Exploring FPGA Graphics. It’s time to turn our attention to drawing. Most modern computer graphics come down to drawing triangles and colouring them in. So, it seems fitting to begin our tour of drawing with triangles and the straight lines that form them. This post will implement Bresenham’s line algorithm in Verilog, creating lines, triangles, and even a cube (our first sort-of-3D graphic). This post was last updated in January 2022. Read more

31 December 2020

Verilog Lint with Verilator

Hardware design can be unforgiving, so it pays to use any advantage you can get. Verilator is a Verilog simulator and C++ compiler that also supports linting: statically analysing your designs for issues. Not only can Verilator spot problems your synthesis tool might overlook, but it also runs quickly. Verilator is also great for graphics simulation with SDL. This post was last updated in July 2021. Get in touch: GitHub Issues, 1BitSquared Discord, @WillFlux (Mastodon), @WillFlux (Twitter) Read more

22 December 2020

Square Root in Verilog

The square root is useful in many circumstances, including statistics, graphics, and signal processing. In this FPGA recipe, we’re going to look at a straightforward digit-by-digit square root algorithm for integer and fixed-point numbers. There are lower-latency methods, but this one is simple, using only subtraction and bit shifts. This post was last updated in June 2021. This post is part of a series of handy recipes to solve common FPGA development problems. Read more

11 November 2020

iCE40 FPGA Toolchain on Linux

Since I tested FPGA development tools on Ubuntu 20.04, there have been requests for more posts on FPGA tooling. In this post, I provide a quick guide to building an open-source FPGA toolchain for iCE40 boards, such as iCEBreaker. I plan to cover ECP5 FPGAs in a future version. This post was last updated in February 2022. This guide is designed for Ubuntu or Pop!_OS 20.04, but should be straightforward to adjust to your own distro. Read more

4 November 2020

Hello Nexys - Part 1

This three-part tutorial provides a quick introduction to FPGA development with SystemVerilog and the Digilent Nexys Video board. No prior experience of FPGA development is required, but basic knowledge of programming concepts is assumed. If you can write a simple program with Python or JavaScript, you shouldn’t have any trouble. This post was last updated in June 2021. I find working with FPGAs gives me a sense of delight so often lacking in modern software development. Read more

30 October 2020

Framebuffers

Welcome back to Exploring FPGA Graphics. In the previous two parts, we worked with sprites, but another approach is needed as graphics become more complex. Instead of drawing directly to the screen, we draw to a framebuffer, which is read out to the screen. This post provides an introduction to framebuffers and how to scale them up. We’ll also learn how to fizzlefade graphics Wolfenstein 3D style. In the next part, we’ll use a framebuffer to visualize a simulation of life. Read more

28 October 2020

Hardware Sprites

Welcome back to Exploring FPGA Graphics. In the previous part, we updated our display signals and learnt about colour palettes. This part shows you how to create fast, colourful graphics with minimal logic. Hardware sprites maintain much of the simplicity of our Pong design while offering greater creative freedom. This post was completely revised in June 2022. In this series, we explore graphics at the hardware level and get a feel for the power of FPGAs. Read more

22 September 2020

Life on Screen

Welcome back to Exploring FPGA Graphics. In this post we’re going to use the designs we created in Framebuffers to experiment with Conway’s Game of Life. This post was last updated in January 2022. In this series, we explore graphics at the hardware level and get a feel for the power of FPGAs. We’ll learn how displays work, race the beam with Pong, animate starfields and sprites, paint Michelangelo’s David, simulate life with bitmaps, draw lines and shapes, and create smooth animation with double buffering. Read more

24 August 2020

FPGA Memory Types

Designing with FPGAs involves many types of memory, some familiar from other devices, but some that are specific to FPGAs. This FPGA recipe gives a quick overview of the different flavours, together with their strengths and weaknesses, and some sample designs. This guide includes external memory types, such as SRAM and HBM, that are used in CPUs and GPUs, so much of what is said here is generally applicable, but the focus is on FPGAs. Read more

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