*bump*

I think even Calc84maniac doesn't, but again, I could be wrong. Maybe you might have more luck with Goplat.

Well, at that point, I didn't know how to access the TI-84+ link port through ARM assembly. Now I do, but I no longer have the source code for the TI-83+ emulator.

Now I'm just hoping he notices

Calc84maniac and I were chatting last knight about how to fix this, and this is how you do both of our issues:
Access the link port:
To enable the link port, OR the value at 0x900A0000 with 0x20.
To disable, AND the same value with ~0x20.
Change the first two bits of 0x90100000 to reflect the state of the ring and tip, respectively.
Interrupts:
Back up the value at 0x38 first.
Load your own interrupt function into 0x38 by using &functionname to get a pointer to it.
Restore 0x38 upon leaving.

That would be a great explanation

I haven't tried USB, and this is intended to use the I/O port on an 84+ keypad.
okay...
Sounds weird but I'll go with it.
I got sound to work now, it plays a tone, and pressing up and down on the keypad changes the tone.
The following code should play some sort of noise, but it only plays a high pitched tone:
int main(void) {
enableLink();
clearScreen();
FILE* wavFile = fopen("HBFS.wav", "r");
char currentSampleLeft, currentSampleRight;
while (!isKeyPressed(KEY_84_ENTER))
{
}
while (!isKeyPressed(KEY_NSPIRE_ESC) && !isKeyPressed(KEY_84_CLEAR))
{
fread(&currentSampleLeft, 1, 1, wavFile);
fread(&currentSampleRight, 1, 1, wavFile);
int count;
for (count = 0; count <= 0xFF; count++)
{
int value = 0;
if (count < currentSampleLeft)
{
value++;
}
if (count < currentSampleRight)
{
value += 2;
}
KEYPAD_84_IO = value;
}
}
fclose(wavFile);
disableLink();
return 0;
}

void enableLink()
{
MISC_PORTS |= 0x20;
}

void disableLink()
{
MISC_PORTS &= ~0x20;
}Any ideas?

Well, right now what I have is static with the faintest inklings of the occasional tone, so I have a long way to go.