Technology Blogs

We play with technology. Sometimes we discover things we think are worth sharing.
Radix-n Fast Fourier Transforms (Part 1)
VHDL

Radix-n Fast Fourier Transforms (Part 1)

FFTs are generally defined recursively, so how hard can it be to write a recursive VHDL implementation of an FFT that can scale to any number of inputs for any chosen radix?
Compiling VHDL For The Missing Fixed And Floating Point Libraries
VHDL

Compiling VHDL For The Missing Fixed And Floating Point Libraries

VHDL-2008 has added types sfixed, ufixed and float for fixed and floating point arithmetic, but you may struggle to use them with older tools. Here's how to fix that.
FIR Filter Implementation Comparisons
VHDL

FIR Filter Implementation Comparisons

Having created the pipelined adder tree component, time to compare it with other implementations to see what value it adds.
Adder Trees Pipelined Efficiently by Recursion
VHDL

Adder Trees Pipelined Efficiently by Recursion

Amusing myself with recursive structures in HDL that are entirely synthesisable and optimal in both size and clock speed. This is primarily a hierarchical construction problem made interesting by having to copy with a non-balance tree.
Notes on Fixing Hold Time Violations
FPGA

Notes on Fixing Hold Time Violations

Gathering advice on how to fix hold time violations with an emphasis on FPGA design.
Cygwin Mirror and Installation
Bash

Cygwin Mirror and Installation

Ensuring that your whole team has the same repeatable installation of Cygwin. How to mirror Cygwin on to local infrastructure such that you can script the installation to be the same for everyone.
Comparison of ModelSim 'Signal Spies' and VHDL 'External Signals'
VHDL

Comparison of ModelSim 'Signal Spies' and VHDL 'External Signals'

Example uses of ModelSim's Signal Spies and VHDL-2008's External Signals.
Using Python Decorators
Python

Using Python Decorators

A python decorator allows you to remove repeated code by passing function into another function which extends it.
Deriving AXI Crossbar Address Maps
FPGA

Deriving AXI Crossbar Address Maps

Some tips and tricks for correctly decoding an AXI crossbar address map.