We play with technology. Sometimes we discover things we think are worth sharing.

Tag: "quartus"

Taking Xilinx's Advice on Reducing Routing Congestion
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.
Getting Started with FPGA and VHDL
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.
Radix-n Fast Fourier Transforms (Part 3)
VHDL

Radix-n Fast Fourier Transforms (Part 3)

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.
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.
Large Comparators Pipelined Efficiently by Recursion
VHDL

Large Comparators 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 mathematics problem, and once the VHDL construction has been completed, the EDA tools have a final twist.