Ovl-upload : On-demand Overlay uploading on the PSX

This example code demonstrates (as opposed to this gif above) how to use the companion 'ovl-upload.py' script that should be provided with this file.

Once the code is loaded on a unirom enabled PSX via a serial/USB cable, 'ovl-upload.py' listens for a specific command

to load an overlay file on demand.

For an explanation about overlays, see http://psx.arthus.net/sdk/Psy-Q/DOCS/TRAINING/FALL96/overlay.pdf

For a basic example see @JaberwockySeamonstah's https://github.com/JaberwockySeamonstah/PSXOverlayExample

Thanks

@JaberwockySeamonstah, @JonathanDotCel, @nicolasnoble, @Lameguy64 for their help and patience.

Set-up

• You need to set up the Nugget+PsyQ SDK, as described here : https://github.com/ABelliqueux/nolibgs_hello_worlds
• Clone this repo.
• Get Unirom + NotPSXserial.
• Get mkpsxiso.
• With your PSX on at the unirom prompt, serial/USB cable plugged, upload the default data at the right address :

# We need debug mode for runtime data uploading

nops /debug /dev/ttyUSB0

nops /fast /bin 0x8003e5c8 Overlay.ovl0

nops /fast /exe ovl-upload.ps-exe

nops /slow

You should see a cube on a blue background.

• In a terminal/cmd, launch the python script ./ovl-upload.py. You should see a message : Listening for incoming data...

• Push the select button on your controller. The cube should change shape ! In reality, we are loading the geometry data from another file : Overlay.ovl1

Alternatively, you can use the bin/cue in an emulator or xstation.

Helper scripts are provided for convenience and are dependent on pcsx-redux and mkpsxiso being in your $PATH.

• isotest.sh will make, build the bin/cue, and open the resulting image in pcsx-redux.
• ovly-upload-helper.sh is a small wrapper for nops, hence depending on it being in your $PATH, that takes 4 args : load address, overlay filename, ps-exe filename and optional comport/serialdevice - e.g :

# make &&
./ovly-upload-helper.sh 0x8003e5c8 Overlay.ovl0 ovl-upload.ps-exe /dev/ttyUSB0