Scratch VHDL

Logo

The purpose of "Scratch VHDL" is to make reprogrammable logic design into child's play. Sounds ambitious.

View the Project on GitHub house-of-abbey/scratch_vhdl

Simulation

Controls & Display

We avoid the need to write a VHDL test bench by substituting the stimulus VHDL code with a graphical user interface to control the inputs and display the outputs. In order for this to work it is necessary to start the simulation from the batch file run_sim.cmd, which loads the TCL scripts necessary to make this work.

Simulation Controls

The controls comprise:

Testing

A test bench is used to provide the clock and reset. After that all the stimulus comes from the graphical controls, and the LED outputs drive the display panel.

Test Setup

This is an alternative to writing VHDL stimulus in the test bench and keeps the test process engaging and interactive at the expense of repeatability. It does therefore skip a realistic step in development of tests.

Debug

The simulation Wave window must still be used for debugging the wave forms created from the button presses.

Simulation Wave Window