Checking that control set remapping delivers on the Xilinx promises.
FPGA
Taking Xilinx's Advice on Reducing Routing Congestion
I've been faced with the situation where the tools fail to create an image that meets timing, complaining about routing congestion. Here are some anecdotes about trying to follow Xilinx's advice.
FPGA
Getting Started with FPGA and VHDL
I've been asked a few times how one gets started with FPGA design? Here are a few notes on the tools you can download for free and the existing websites that already cater for teaching VHDL.
FPGA
Verification of Clock Domain Crossing Topologies
There are too many ways in which it is possible to mess up clock domain crossings in digital electronics. This post explores Xilinx's report_cdc TCL command and how well it recognises some of the risks you may have missed.
FPGA
Verification of Clock Domain Crossing Timing Constraints and Exceptions
Applying timing exceptions for synchronising registers when crossing clock domains, and verifying the exceptions have been correctly applied and others have not been missed.
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?
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.
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.
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.
