961 VGA Timing Experiments
961 : VGA Timing Experiments
- Author: Rebecca G. Bettencourt
- Description: Configurable VGA signal generator for experimentation purposes.
- GitHub repository
- Open in 3D viewer
- Clock: 0 Hz
How it works
Generates VGA signals. All signal timings (display area, front porch, back porch, hsync, vsync, polarity) are fully configurable and several test patterns are included to enable experimentation.
How to test
Connect to a VGA monitor. Set ui_in[3:0] all LOW and pulse ui_in[7] to
set signal timings to a "known good" configuration of 640×480 at 60Hz.
Observe the vertical color bars. Set either ui_in[0] or ui_in[1] HIGH
and pulse ui_in[7] to change the displayed test pattern.
Set ui_in[3:0] to a register address, set {ui_in[6:4], uio_in} to a
register value, and pulse ui_in[7] to change individual timing values.
(When setting hsync width or vsync height, set ui_in[6] HIGH for
positive polarity or LOW for negative polarity.)
| Address | Description | Default |
|---|---|---|
| 0 | Reset. | |
| 1 | Next pattern. | |
| 2 | Previous pattern. | |
| 3 | Pattern number. | 31 |
| 4 | Horizontal visible width. | 640 |
| 5 | Horizontal front porch (right border). | 16 |
| 6 | Horizontal sync width (polarity on ui_in[6]). |
96 |
| 7 | Horizontal back porch (left border). | 48 |
| 8 | Vertical visible height. | 480 |
| 9 | Vertical front porch (bottom border). | 10 |
| 10 | Vertical sync height (polarity on ui_in[6]). |
2 |
| 11 | Vertical back porch (top border). | 33 |
| 12 | Pattern color. | 0 |
| 13 | Next color. | |
| 14 | Previous color. | |
| 15 | Reset. |
| Pattern | Description |
|---|---|
| 0 | Solid color. |
| 1 | 1×1 pixel checkerboard. |
| 2 | 2×2 pixel checkerboard. |
| 3 | 4×4 pixel checkerboard. |
| 4 | 8×8 pixel checkerboard. |
| 5 | 16×16 pixel checkerboard. |
| 6 | 32×32 pixel checkerboard. |
| 7 | 64×64 pixel checkerboard. |
| 8 | 8×8 pixel grid. |
| 9 | 16×16 pixel grid. |
| 10 | 32×32 pixel grid. |
| 11 | 64×64 pixel grid. |
| 12 | 1×1 pixel color table. |
| 13 | 2×2 pixel color table. |
| 14 | 4×4 pixel color table. |
| 15 | 8×8 pixel color table. |
| 16 | 16×16 pixel color table. |
| 17 | 32×32 pixel color table. |
| 18 | 1×1 pixel color antidiagonal lines. |
| 19 | 2×2 pixel color antidiagonal lines. |
| 20 | 4×4 pixel color antidiagonal lines. |
| 21 | 8×8 pixel color antidiagonal lines. |
| 22 | 16×16 pixel color antidiagonal lines. |
| 23 | 32×32 pixel color antidiagonal lines. |
| 24 | 1×1 pixel color diagonal lines. |
| 25 | 2×2 pixel color diagonal lines. |
| 26 | 4×4 pixel color diagonal lines. |
| 27 | 8×8 pixel color diagonal lines. |
| 28 | 16×16 pixel color diagonal lines. |
| 29 | 32×32 pixel color diagonal lines. |
| 30 | Horizontal color bars. |
| 31 | Vertical color bars. |
External hardware
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | A0 | R1 | D0 |
| 1 | A1 | G1 | D1 |
| 2 | A2 | B1 | D2 |
| 3 | A3 | VSync | D3 |
| 4 | D8 | R0 | D4 |
| 5 | D9 | G0 | D5 |
| 6 | D10 | B0 | D6 |
| 7 | WE | HSync | D7 |