Once you have a installed Libre-FDATool compatible Python environment or
a deployed Libre-FDASys virtual appliance, you must execute the
librefdatool.py* script to launch the GUI. Then, follow this tutorial
for a quick-start.
Libre-FDATool working mechanism is very simple. It works as a basic
filter simulator, in which you define a stimulus, then configure a
filter and finally execute a simulation.
In the GUI, there is a tab for each of the basic steps -- stimulus,
filter and simulator.
HDL code generation is automatically executed when a simulation is
Here we have a quick description of the different GUI tabs that control
In the stimulus tab, we can configure the signal that is going to be
sourced to the filter. Here, w can modify the waveform type, frequency,
In the filter tab, we define the filter that is going to be used.
There are two basic configuration blocks:
Hardware Realization: here, the different HDL model parameters
are defined, such as the filter structure or the Fixed Point
configuration for coefficients and input/output ports
Filter Parameters: in this configuration box, we can select
different high-level filter specs recipes in order to calculate the
LTI system coefficients. There are different configurable parameters
for every FIR or IIR filter recipe, such as window method, order,
Once we have configured the filter, we can analyze the expected transfer
function for both exact floating point and digital HDL
In the simulator tab, we have the controls for choosing which simulator
engine Icarus Verilog / GHDL and HDL language Verilog / VHDL we want to use.
In addition we can choose the name for the filter UUT and the workspace
folder. When a simulation is performed, the correspondent HDL files for
device and testbench are automatically generated on the workspace folder
using the assigned
In order to launch a simulation, we must click on the gear button placed
on the toolbar. This button is accessible from any tab, and when the
simulation has finished, Libre-FDATool will automatically open the
In the simulator tab scope we can see the respective filtered signals
for both floating point model and digital HDL simulation. We can choose
to view the response in time, plot the absolute error or estimate the