VHDL tutorial - A practical example - part 1 - Hardware
Gene Breniman walks through a practical CPLD-based data acquisition engine built for a low-power handheld instrument, focusing on hardware choices, signal flow, and pin assignments. The article explains component selection including a PCM1870 ADC, CY14B101Q2 serial nvSRAM, and an XC2C64A CPLD, and shows how the CPLD acts as an SPI sequencer and I2S clock master while minimizing microcontroller pins and power draw.
Introduction to FPGA Technology
Muhammad Yasir lays out a concise primer on FPGA fundamentals, covering internal architecture, vendors, and practical selection criteria. He explains how logic cells, LUTs, flip-flops, carry chains, block RAM, and I/O blocks combine to determine capacity and performance. This friendly overview shows why FPGAs beat ASICs for low-volume or rapidly changing designs, and how to match device resources to your application needs.
FPGA Bloggers Needed - New Reward System
You can earn up to $500 for a single FPGA blog post on FPGARelated. Stephane Boucher announces a new pageview-based reward system that pays $25 for every 250 unique pageviews, capped at $500 when a post reaches 5,000 views. If you write about Verilog, VHDL, or FPGA design and want to share expertise while getting paid, fill the short application form to apply.
USB-FPGA : Introduction
Christopher Felton recounts a six-year hobby project to build an open-source USB-FPGA board and its toolchain, from PCB to gateware, firmware, and PC software. He explains why the Cypress FX2 and a Spartan3 were chosen, how the USBP framework supported multiple boards, and why the project’s open-source ambitions didn’t attract the collaboration he expected. Expect practical design and community lessons.
Half-band filter on Xilinx FPGA
Lyons Zhang shows a practical, high-throughput implementation of a symmetric systolic half-band FIR on Xilinx FPGAs using DSP48 slices. The post includes a two-channel interleaved downsample-by-2 Verilog module, pipeline mapping to DSP48, and a symmetric rounding trick to reduce the DC shift from truncation. It highlights performance-and-latency tradeoffs and gives working code you can drop into a Spartan-6 style flow.
A Bit Bucket had Holes
Christopher Felton looks back at TierLogic's multi-layer FPGA idea and its recent shutdown, contrasting it with Tabula's virtual 3D approach. He asks whether physical-layer stacking could have delivered the ultra-high logic density some designs need, especially at modest clock rates and small footprints. The post highlights how funding, market fit, and patent outcomes often decide whether neat FPGA tech becomes a product.
Developing FPGA-DSP IP with Python
Designing FPGA-DSP IP entirely in Python is practical and productive, as Christopher Felton demonstrates using MyHDL. He shows how numpy and scipy handle the signal design while a SIIR class generates RTL, enables side-by-side floating-point and HDL simulation, and converts to Verilog for synthesis. The post includes Xilinx XC3S500E resource results and a link to the SIIR source on BitBucket, making it easy to try the workflow.
Holy Bit Bucket
Christopher Felton reacts to Tabula's 'Spacetime' pitch, which claims an 8x boost in LUT density by time-division multiplexing internal logic. He urges caution, comparing Tabula to Achronix and pointing out that early parts will likely target high-end networking and carry premium pricing. The post argues inexpensive development boards will be crucial for wider adoption.
The Spartans
Christopher Felton walks through the Spartan6 FPGA basics, explaining CLBs, slices, and the new 6-input LUTs while comparing them to Spartan3. He ran timing-driven mappings of real gateware to show practical LUT utilization differences. The post gives a pragmatic estimate of expected LUT savings and points out where mapping results can vary depending on the design.
New Design - Finally!
Stephane has finally applied a modern design to FPGARelated.com, bringing the site in line with DSPRelated.com and EmbeddedRelated.com. After a long todo list the refreshed layout and updated styling are live, promising a cleaner, more consistent experience across his engineering sites. Drop by to explore the new look and share feedback with the author.
Summer of gateware is coming (again)
Wondering what gateware will come out of this summer? Christopher Felton announces MyHDL is back in Google Summer of Code and has been awarded six student slots. Projects span GEMAC, a Leros tiny processor, JPEG encoder front/backends, RISC-V tooling and HDMI+RISC-V work. Follow along for short project updates and a final summer summary.
Designing Embedded System with FPGA - 1
Getting an embedded system running on an FPGA is much simpler than it sounds when you use Xilinx EDK and a soft processor. Pragnesh Patel walks through a beginner-friendly approach using the MicroBlaze CPU, drag-and-drop IP cores, and a Spartan-3E starter kit so you can assemble peripherals without deep VHDL knowledge. The post focuses on the EDK base system builder and first setup steps to generate a working design.
MyHDL ... MyPWM
Christopher Felton presents a compact MyHDL PWM engine designed to be configured at design time and targeted for FPGA synthesis. The module derives PWM bit width from the system clock frequency and desired pwm_frequency, truncates inputs when necessary, and prints parameter summaries for different clock/pwm combinations. The post includes the full MyHDL source and a simulation waveform showing the input signal and the modulated output, making it easy to reproduce.
MyHDL FPGA Tutorial II cont. (Echo, Audio Interface)
Christopher Felton walks through connecting an FPGA to a TI AIC23 audio codec using MyHDL, covering SPI register programming and I2S streaming. The post explains how the AIC23 module decodes I2S into parallel samples with a Ts sample-valid strobe and how startup SPI writes configure sample width and rate. You get a simple loopback/echo testbench and practical notes on 16/24/32-bit sample handling.
New Design - Finally!
Stephane has finally applied a modern design to FPGARelated.com, bringing the site in line with DSPRelated.com and EmbeddedRelated.com. After a long todo list the refreshed layout and updated styling are live, promising a cleaner, more consistent experience across his engineering sites. Drop by to explore the new look and share feedback with the author.
Cutting a Path Forward
As a software developer building a drone navigation prototype, the author turned to FPGAs after realizing CPUs and cloud tethering break the "simple, cheap, reliable" constraints. He proposes mapping sensor probabilities into a graph-cut network using negative log-likelihoods to produce risk‑averse, real‑time path planning, aiming for tens of milliseconds. The post explains the graph-cut idea, cites FPGA precedents, and lays out a practical FPGA-focused plan of attack.
Choosing an Implementation Approach
I outline why I chose a CPU-like Graph Cut Processing Unit for FPGA-based graph-cut work, contrasting whole-problem and streaming approaches from the literature. The plan maps push-relabel style augmenting-path iterations to a simple GCPU state machine and pseudocode, prioritizing staged, testable development now and leaving highly parallel streaming scaling for later.
State Machine ‘v’ Micro in a FPGA
A CPU is just a big state machine, but that doesn't mean you always need one in your FPGA. Paul compares hand-written state machines, soft-core CPUs, and standalone microcontrollers, highlighting speed, flexibility, cost, and complexity tradeoffs. Read this if you want a practical way to decide whether to add more state machines, a small soft core, or a separate MCU to your next design.
Designing a FPGA Micro Pt1 - Start The Clock
Paul J Clarke takes on cloning a Microchip PIC12F509 inside an FPGA, picking it for its tiny, well-documented architecture. He outlines the core pieces you'll need: 1024×12-bit ROM, 41 bytes of RAM, an ALU, status register, program counter with a two-level stack, GPIO, and the PIC's unusual four-phase internal clock. This post sets the plan and previews the next installment with the first implementation work.
Are you kidding me?
Christopher Felton pushes back on the idea that C/C++/SystemC are the natural path to higher-abstraction FPGA design. He argues hardware designers often do not use C-family languages for modeling and simulation, so choosing C as the HLS lingua franca may be more about tool momentum than suitability. The post urges reconsidering languages with higher abstraction and lower cost of entry for system modeling and HLS.
Homebrew CPUs: Color Languages
Victor Yurkovsky proposes turning color from mere syntax highlighting into a semantic tool for a Forth-like CPU, letting color pick which stack an operation touches. He outlines a "Rainbow Forth" where green and blue select two datastacks, red denotes the return stack, gray means use the caller's color, and white is neutral. The post sketches CPU changes, a COLOR register, call encoding and immediate-mode coloring, and teases editor and compiler implications for implementing this idea on a J1-style core.
MyHDL ... MyPWM
Christopher Felton presents a compact MyHDL PWM engine designed to be configured at design time and targeted for FPGA synthesis. The module derives PWM bit width from the system clock frequency and desired pwm_frequency, truncates inputs when necessary, and prints parameter summaries for different clock/pwm combinations. The post includes the full MyHDL source and a simulation waveform showing the input signal and the modulated output, making it easy to reproduce.
Cutting a Path Forward
As a software developer building a drone navigation prototype, the author turned to FPGAs after realizing CPUs and cloud tethering break the "simple, cheap, reliable" constraints. He proposes mapping sensor probabilities into a graph-cut network using negative log-likelihoods to produce risk‑averse, real‑time path planning, aiming for tens of milliseconds. The post explains the graph-cut idea, cites FPGA precedents, and lays out a practical FPGA-focused plan of attack.
Point of View
Christopher defends a straightforward MyHDL RTL description of a FIR filter, arguing it is explicit, readable, and concise. He compares that style to a functional hardware description built with Python primitives and list comprehensions, and finds both convert to identical synthesis resources for this example. The post highlights readability tradeoffs and suggests choice often comes down to background and preference.
Are you kidding me?
Christopher Felton pushes back on the idea that C/C++/SystemC are the natural path to higher-abstraction FPGA design. He argues hardware designers often do not use C-family languages for modeling and simulation, so choosing C as the HLS lingua franca may be more about tool momentum than suitability. The post urges reconsidering languages with higher abstraction and lower cost of entry for system modeling and HLS.
[Comments] C HLS Benefits
Christopher Felton argues C-to-gate HLS showed little advantage in his median calculation comparison with MyHDL. He explains the test mixes language paradigm and abstraction: Vivado C HLS is an imperative, step-by-step style while MyHDL offers a concurrent, HDL-level description with Python's readability and elaboration features. He notes C-HLS can help if you only know C, but for massively parallel FPGA work non-C tools may be preferable.
Choosing an Implementation Approach
I outline why I chose a CPU-like Graph Cut Processing Unit for FPGA-based graph-cut work, contrasting whole-problem and streaming approaches from the literature. The plan maps push-relabel style augmenting-path iterations to a simple GCPU state machine and pseudocode, prioritizing staged, testable development now and leaving highly parallel streaming scaling for later.
Summer of gateware is coming (again)
Wondering what gateware will come out of this summer? Christopher Felton announces MyHDL is back in Google Summer of Code and has been awarded six student slots. Projects span GEMAC, a Leros tiny processor, JPEG encoder front/backends, RISC-V tooling and HDMI+RISC-V work. Follow along for short project updates and a final summer summary.
MyHDL Presentation Examples
Christopher Felton collected slide-ready MyHDL demos he used at EELive and PyOhio, making it easy to see practical HDL examples in action. The post explains the tradeoffs behind single-slide examples, links to 2013 and 2014 demos from simple FPGA hello-worlds to filters and a VGA system, and points readers to the repository where full and larger examples live for reuse.
What do Ohio, Python, and FPGAs have in common?
Christopher Felton is bringing MyHDL, Python, and hands-on FPGA work to the free pyohio regional conference on July 27-28. His informal talk introduces programmable hardware to imperative thinkers, contrasts FPGAs with modern computers, and showcases the MyHDL package. The follow-up workshop lets Python programmers edit an example, configure a Xess development board, and see their changes run on real hardware.
