Proper USB Storage and SD(HC) Handling in C for Wii Homebrew

Handling File IO is another popular topic in Wii Hombrew for obvious reasons and one that I've spent a significant amount of time on. I'm going to use this post demonstrate proper initialization and deinitialization of SD(HC) and USB devices in C. There are in fact quite a few different ways to do it but I've refined my personal methodology over years of carefully tweaking it and testing it in many apps.

I'm going to walk through initializing and deinitializing both devices since you probably want to use both as a developer.

So the first thing that needs to be done is to include libfat. To do this add to your header:

#include (sdcard.h/wiisd_io.h)

#include (fat.h)

Then add -lfat under LIBS: in your makefile.

Now let's read some code. These are functions for how I initialize and deinitialize the SD(HC) device plugged in:

void InitSD(){

fatUnmount("sd:/");

__io_wiisd.shutdown();

fatMountSimple("sd", &__io_wiisd);  

}

void DeInitSD() {

fatUnmount("sd:/");
__io_wiisd.shutdown() 

} 

These are functions for how I initialize and deinitialize the USB Storage device plugged in:

void InitUSB(){

fatUnmount("usb:/"); 

bool isMounted = fatMountSimple("usb", &__io_usbstorage);

if(!isMounted){

fatUnmount("usb:/");

fatMountSimple("usb", &__io_usbstorage);

bool isInserted = __io_usbstorage.isInserted();

if(isInserted) {

int retry = 10;

while(retry) { 

isMounted = fatMountSimple("usb", &__io_usbstorage);

if (isMounted) break;

sleep(1);

retry--;

}

}          

} 

void DeInitUSB() {

fatUnmount("usb:/");

__io_usbstorage.shutdown(); 

}

A quick note on the USB code is that it looks startlingly simple compared to what others do and that I've actually never seen it fail on any USB Storage device (so long as it's formatted to NTFS or fat32 of course). I'm always trying to improve my code however so please feel free to pitch suggestions my way. Alternatively, sven from Team Twiizers has written an excellent USB Storage driver in C (a copy of it can be found here) which offers many additional functions aside from just initializing and deinitializing the USB Storage device.

C++ developers can grab a copy of my DOP-Mii Library which provides an excellent wrapper for initializing and deinitializing these storage devices as well as a few additional functions which work as wrappers for some of sven's USB Storage functions.

As always I hoped this helped out a fellow dev. Always feel free to leave questions in the comments below or in my inbox at castlevania7689@yahoo.com