Implement direct SD card access via libdragon filesystem API.

[browntownington]

Not an issue :) but more a question.

I came across your repo for ED64 Tools and when I saw "Implement direct SD card access via libdragon filesystem API." I got super excited. As I have been for a long time wanting to do a raspberry pi mod to my flash cart so I can sync game saves and modify gameshark cheats over wifi.

I'm curious how this feature is coming along or how you are thinking to implement it. I tried to browse the Libdragon API to find what it possible with the file system. Is this what you're planning to use? (https://libdragon.dev/ref/group__system.html)

[anacierdem]

This is something I have implemented on libdragon and that todo item is actually done. I may add some explanation here to use it but basically it should work with; fopen("sd:/<filename>", flags). There may be unsupported use cases as we haven't fully tested it though. I know for certain that it works for the most part.

[browntownington]

Oh wow that's great news! I just ordered an X7 - I'll have to wait to try this.

Though I may have to wait for more of an explanation and/or example as I think I might of confused the purpose of this feature.

At first I thought this may allow for SD card filesystem access over usb. But after reading some more, I think this is more for a homebrew ROM to leverage SD card file system instead?

[anacierdem]

It might not be very useful for a final homebrew ROM as SD access is relatively slow. Also on libdragon it is only enabled as a debug feature IIRC (behind NDEBUG) so you may need to build with all the assertions etc. when you use it at its current state.

This is something that I want to experiment with as well b/c it will allow fast ROM uploads over USB while still having all the assets on the onboard SD card albeit slow. It will be a great development feature indeed but we will see if it would be useful in a final rom as it will be dependent on a development cartridge.

[anacierdem]

@browntownington I think I misunderstood you last time :) having a rom to enable sd card access over USB is a great idea indeed! I can try implementing it sometime.