Virtual 7-Segment Display Generator for the Papilio Arcade

Here’s some more user-contributed code from reader Alex, this time on making a virtual 7-segment display on the Papilio Arcade in VHDL.

The 7-segment display is outputted to VGA, and can be used to superimpose alphanumeric characters on top of any video already coming out on VGA.  The position, size, and color of the 7-segment alphanumeric characters is completely up to how you code them.

From Alex’s write-up:

“Seven segment displays are useful for showing data, debug info such as addresses, etc. Instead of using a physical expansion board (wing) which costs money and has a limited number of digits, this simply uses an existing VGA output on a wing to implement any number of seven segment displays limited only by the available screen real estate.”

Be sure to check out Alex’s code for the display generator here.  We’ve included both the code and Alex’s synopsis after the jump.

Thanks again to Alex – always on point, man!

Readers: how would you implement this in your own projects?  Make your voice heard in the comments!

Virtual Seven Segment Display Generator

Author – Alex

Source Code

Source code on Google Code

Overview

VHDL Project for the Papilio Arcade MegaWing

Implements virtual seven segment displays on a VGA screen. Tested with a Papilio Plus FPGA and MegaWing, but should work on any platform due to the simplicity of the code.

Seven segment displays are useful for showing data, debug info such as addresses, etc. Instead of using a physical expansion board (wing) which costs money and has a limited number of digits, this simply uses an existing VGA output on a wing to implement any number of seven segment displays limited only by the available screen real estate.

In principle, if your project already uses the VGA output such as say PacMan, if should be quite easy to superimpose the seven segment display on top of the existing video output by logical ORing the seven segment display output with the existing VGA signal.

The position, size and color of each digit is configurable. A simplistic demo top module is included to generate some static and dynamic digits of various sizes and colors, see picture below.

Pictures