RGB Panel driver for iCEBreaker board
=====================================

This is an example usage of the Hub75 driver IP in this repository
and implements driving RGB panels using the iCEBreaker board along
with the RGB Panel PMOD.

Default configuration is for a 64x64 panel using 1:32 multiplex.
Note that some panels have the Red and Blue channels swapped, so
you might have to adapt this ...

This example has 3 modes of operations explained below. Each
mode is selected by uncommenting the appropriate `define` at the
top of the `top.v` file.


Pattern mode
------------

This generates a Red & Blue gradient across the two axises and then some
moving green lines across. Very simple example of generating data directly
on the FPGA itself and can also be used as a pretty reliable test that all
works well.


Video play mode
---------------

In this mode, frames are read from the SPI flash and displayed in sequence.

For this to work, you need some video content to be preloaded into the flash.
You can use the special `make data-prog` target to load a default nyan cat
animation.

To load your own animation in flash, checkout the `ADDR_BASE` and `N_FRAMES`
parameters that tell the module where to look in flash for the image data.
It needs to be raw frames, pixel format is either in `RGB332` or `RGB565`
or `RGB888` depending on the `BITDEPTH` you selected. (Default is 16 bits and
`RGB565`).


Video streaming mode
--------------------

In this mode, video content is streamed from the host PC to the FPGA using
SPI (through the FT2232H used for programming the FPGA).

A control software `stream.py` is provided in the `sw/` sub-directory.
It required Python 3.x and [pyftdi](https://github.com/eblot/pyftdi).

And example usage would be :

```
./stream.py --fps 10 --loop --input ../data/nyan_glitch_64x64x16.raw
```

See the `--help` for other options available.

To prepare content, you can use ffmpeg :

```
ffmpeg -i input.mp4 -filter_complex "[0:v]crop=540:540,scale=64:64" -pix_fmt rgb565 -f rawvideo output.raw
```

Obviously the number for the `crop` filter need to be adjusted for your source
material to get a square image that selects the best region to show. Also, you
can do use unix FIFOs to directly pipe content from `ffmpeg` to the `stream.py`
application without the need for intermediate files.