MyHDL synthesis: from browser to FPGA in five seconds
Martin Strubel walks through how modern open-source tooling slashes the pain of converting super-HDLs into FPGA-ready firmware. Instead of long translation chains from MyHDL or nMigen into Verilog or VHDL, yosys and its Python API let you build synthesizeable primitives on the fly, inspect schematics, and emit synthesized Verilog or firmware quickly. The post explains the shift from toolchain friction to fast browser-to-FPGA workflows.
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.
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.
Running Average
This post shows a lightweight running average variant that cleans up noisy wheel-encoder timing using a shift-based divide-by-8 and a small rounding constant. The filter updates as M1 = M0 + (t0 - A0), where A0 is estimated from the previous average, so each new measurement nudges the estimate rather than immediately replacing it. It trades exact oldest-sample subtraction for low resource cost and strong noise suppression.
Dealing With Fixed Point Fractions
Fixed-point fractional math is easy to botch, and this post lays out pragmatic ways to avoid those mistakes. It clarifies the difference between integer and fractional overflow, shows how Q notation helps track binary-point scaling, and explains why multiplies add sign bits that may require shifting. Read for concrete FPGA strategies: keeping bit growth, selective shifts, or aggressive normalization, plus testing tips.
Fit Sixteen (or more) Asynchronous Serial Receivers into the Area of a Standard UART Receiver
Michael Morris shows how to pack many asynchronous serial receivers into the area of a single UART by treating FPGA LUTs as writable storage and sharing logic. Using a 4-bit channel counter, microprogrammed state machine, and time-multiplexed baud/sample resources, he fits 16 receive channels (12 used for Caller ID) into a Spartan II XC2S30 and explains input synchronization, filtering, and the multi-channel FIFO approach.
Use Microprogramming to Save Resources and Increase Functionality
Microprogramming can rescue an overfull FPGA, Michael Morris shows, by compressing control logic and time-multiplexing FIFO storage. He replaces an ABEL state machine with a small microprogram ROM that uses block RAM for deep Rx/Tx FIFOs and LUT RAM for pointers and counters, freeing about 25 percent of the device. The article includes Verilog comparisons, resource tables, and a microassembler link to reproduce the approach.
How to start in FPGA development? - Simulation software tools
Nuria Orduna lays out a pragmatic approach to FPGA simulation, comparing Xilinx ISE with integrated ModelSim against a three-tool flow with ModelSim and Precision. She explains why independent ModelSim runs and using notepad++ for VHDL can speed debugging, and why Precision and CoreGen conversions can be painful. Read for a compact, practiced workflow to simplify simulation, synthesis, and project organization.
FPGA Assemblers and Time Machines
Modern FPGA toolchains have turned tinkering into a slog, Victor Yurkovsky recalls the old joy of manual hardware hacking and wants it back. He proposes an assembler-style approach, exemplified by the proposed 'fpgasm', that preserves placement and routing, programs bitstreams in seconds, and makes live probing and rapid iteration practical again. Read this to see why low-level control could revive hands-on FPGA learning.
How to start in FPGA development? - Some tips
Starting from zero, this practical primer walks new FPGA users through the early decisions and habits that make projects work. Nuria Orduna covers how to pick a device, sketch a clear dataflow, prototype in MATLAB or C, organize VHDL entities versus functions, and use ModelSim .do files and testbenches to debug before programming the board. Read it for concise, hands-on starting points.
Dealing With Fixed Point Fractions
Fixed-point fractional math is easy to botch, and this post lays out pragmatic ways to avoid those mistakes. It clarifies the difference between integer and fractional overflow, shows how Q notation helps track binary-point scaling, and explains why multiplies add sign bits that may require shifting. Read for concrete FPGA strategies: keeping bit growth, selective shifts, or aggressive normalization, plus testing tips.
Running Average
This post shows a lightweight running average variant that cleans up noisy wheel-encoder timing using a shift-based divide-by-8 and a small rounding constant. The filter updates as M1 = M0 + (t0 - A0), where A0 is estimated from the previous average, so each new measurement nudges the estimate rather than immediately replacing it. It trades exact oldest-sample subtraction for low resource cost and strong noise suppression.
Fit Sixteen (or more) Asynchronous Serial Receivers into the Area of a Standard UART Receiver
Michael Morris shows how to pack many asynchronous serial receivers into the area of a single UART by treating FPGA LUTs as writable storage and sharing logic. Using a 4-bit channel counter, microprogrammed state machine, and time-multiplexed baud/sample resources, he fits 16 receive channels (12 used for Caller ID) into a Spartan II XC2S30 and explains input synchronization, filtering, and the multi-channel FIFO approach.
Use Microprogramming to Save Resources and Increase Functionality
Microprogramming can rescue an overfull FPGA, Michael Morris shows, by compressing control logic and time-multiplexing FIFO storage. He replaces an ABEL state machine with a small microprogram ROM that uses block RAM for deep Rx/Tx FIFOs and LUT RAM for pointers and counters, freeing about 25 percent of the device. The article includes Verilog comparisons, resource tables, and a microassembler link to reproduce the approach.
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.
MyHDL FPGA Tutorial II (Audio Echo)
Christopher Felton demonstrates how to build an FPGA audio echo using MyHDL by storing delayed samples in BRAM and mixing them back with incoming audio. The project shows parameterizable sample rate, sample width, buffer depth, and conversion from MyHDL to Verilog, with a strong emphasis on test-driven verification and simulation-based resource reports. Read on to see how delay, scaling, and BRAM usage affect real-time audio.
MyHDL synthesis: from browser to FPGA in five seconds
Martin Strubel walks through how modern open-source tooling slashes the pain of converting super-HDLs into FPGA-ready firmware. Instead of long translation chains from MyHDL or nMigen into Verilog or VHDL, yosys and its Python API let you build synthesizeable primitives on the fly, inspect schematics, and emit synthesized Verilog or firmware quickly. The post explains the shift from toolchain friction to fast browser-to-FPGA workflows.
How to start in FPGA development? - Simulation software tools
Nuria Orduna lays out a pragmatic approach to FPGA simulation, comparing Xilinx ISE with integrated ModelSim against a three-tool flow with ModelSim and Precision. She explains why independent ModelSim runs and using notepad++ for VHDL can speed debugging, and why Precision and CoreGen conversions can be painful. Read for a compact, practiced workflow to simplify simulation, synthesis, and project organization.
FPGA Assemblers and Time Machines
Modern FPGA toolchains have turned tinkering into a slog, Victor Yurkovsky recalls the old joy of manual hardware hacking and wants it back. He proposes an assembler-style approach, exemplified by the proposed 'fpgasm', that preserves placement and routing, programs bitstreams in seconds, and makes live probing and rapid iteration practical again. Read this to see why low-level control could revive hands-on FPGA learning.
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.
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.
MyHDL FPGA Tutorial II (Audio Echo)
Christopher Felton demonstrates how to build an FPGA audio echo using MyHDL by storing delayed samples in BRAM and mixing them back with incoming audio. The project shows parameterizable sample rate, sample width, buffer depth, and conversion from MyHDL to Verilog, with a strong emphasis on test-driven verification and simulation-based resource reports. Read on to see how delay, scaling, and BRAM usage affect real-time audio.
Dealing With Fixed Point Fractions
Fixed-point fractional math is easy to botch, and this post lays out pragmatic ways to avoid those mistakes. It clarifies the difference between integer and fractional overflow, shows how Q notation helps track binary-point scaling, and explains why multiplies add sign bits that may require shifting. Read for concrete FPGA strategies: keeping bit growth, selective shifts, or aggressive normalization, plus testing tips.
Running Average
This post shows a lightweight running average variant that cleans up noisy wheel-encoder timing using a shift-based divide-by-8 and a small rounding constant. The filter updates as M1 = M0 + (t0 - A0), where A0 is estimated from the previous average, so each new measurement nudges the estimate rather than immediately replacing it. It trades exact oldest-sample subtraction for low resource cost and strong noise suppression.
Fit Sixteen (or more) Asynchronous Serial Receivers into the Area of a Standard UART Receiver
Michael Morris shows how to pack many asynchronous serial receivers into the area of a single UART by treating FPGA LUTs as writable storage and sharing logic. Using a 4-bit channel counter, microprogrammed state machine, and time-multiplexed baud/sample resources, he fits 16 receive channels (12 used for Caller ID) into a Spartan II XC2S30 and explains input synchronization, filtering, and the multi-channel FIFO approach.
Use Microprogramming to Save Resources and Increase Functionality
Microprogramming can rescue an overfull FPGA, Michael Morris shows, by compressing control logic and time-multiplexing FIFO storage. He replaces an ABEL state machine with a small microprogram ROM that uses block RAM for deep Rx/Tx FIFOs and LUT RAM for pointers and counters, freeing about 25 percent of the device. The article includes Verilog comparisons, resource tables, and a microassembler link to reproduce the approach.
How to start in FPGA development? - Some tips
Starting from zero, this practical primer walks new FPGA users through the early decisions and habits that make projects work. Nuria Orduna covers how to pick a device, sketch a clear dataflow, prototype in MATLAB or C, organize VHDL entities versus functions, and use ModelSim .do files and testbenches to debug before programming the board. Read it for concise, hands-on starting points.
How to start in FPGA development? - Simulation software tools
Nuria Orduna lays out a pragmatic approach to FPGA simulation, comparing Xilinx ISE with integrated ModelSim against a three-tool flow with ModelSim and Precision. She explains why independent ModelSim runs and using notepad++ for VHDL can speed debugging, and why Precision and CoreGen conversions can be painful. Read for a compact, practiced workflow to simplify simulation, synthesis, and project organization.
FPGA Assemblers and Time Machines
Modern FPGA toolchains have turned tinkering into a slog, Victor Yurkovsky recalls the old joy of manual hardware hacking and wants it back. He proposes an assembler-style approach, exemplified by the proposed 'fpgasm', that preserves placement and routing, programs bitstreams in seconds, and makes live probing and rapid iteration practical again. Read this to see why low-level control could revive hands-on FPGA learning.
MyHDL synthesis: from browser to FPGA in five seconds
Martin Strubel walks through how modern open-source tooling slashes the pain of converting super-HDLs into FPGA-ready firmware. Instead of long translation chains from MyHDL or nMigen into Verilog or VHDL, yosys and its Python API let you build synthesizeable primitives on the fly, inspect schematics, and emit synthesized Verilog or firmware quickly. The post explains the shift from toolchain friction to fast browser-to-FPGA workflows.
