559 VGA Glyph Mode
559 : VGA Glyph Mode
- Author: James Ross
- Description: Improved Matrix digital rain animation with 4 VGA modes
- GitHub repository
- Open in 3D viewer
- Clock: 25175000 Hz
How it Works
This is a standalone VGA demo that runs with or without input, replicating The Matrix Digital Rain effect.
Upon circuit reset, the glyphs will appear to fall from the top of the screen.
You can change the palette with the two pins, ui_io[0] and ui_io[1].
NOTE The default VGA timing requires a pixel clock of 25.175 MHz. If you
want to drive higher resolutions, the base clock rate must be adjusted
accordingly with the Clocks table below. You must also set the two pins,
ui_io[6] and ui_io[7], to select your preferred mode.
How to Test
Plug into a VGA monitor and select this circuit to test. By default, the
circuit must be clocked at (or very near) to 25.175 MHz. There are four VGA
timing modes, representing four different display resolutions, which must be
both specifically clocked and have the pins ui_io[7:6] set according to the
following table.
Clocks
Pins 6 and 7 paired with pixel clock
ui_io[7:6] |
Clock (MHz) | VGA Timing Mode |
|---|---|---|
| (default) 0 | 25.175 | 640 x 480 @ 60 fps |
| 1 | 34.96 | 768 x 576 @ 60 fps |
| 2 | 40.0 | 800 x 600 @ 60 fps |
| 3 | 65.0 | 1024 x 768 @ 60 fps |
Additional Palette Input
The circuit accepts two pins ui_io[0] and ui_io[1] for palette selection:
ui_io[1:0] |
Palette |
|---|---|
| (default) 0 | Green |
| 1 | Red |
| 2 | Blue |
| 3 | Pride |
External hardware
Requires the TinyVGA PMOD
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | Palette 0 | R1 | |
| 1 | Palette 1 | G1 | |
| 2 | B1 | ||
| 3 | VSync | ||
| 4 | R0 | ||
| 5 | G0 | ||
| 6 | VGA Mode bit 0 | B0 | |
| 7 | VGA Mode bit 1 | HSync |