Back buttons, jog dial & headphones?

[lardman]

Looking at this thread about enabling the back buttons and jog dial with pdaXrom: https://www.oesf.org/forums/inde...?showtopic=3249

I was wondering how to achieve a similar effect with OZ. In fact I'd be interested to just know how button mapping is handled if anyone would care to enlighten me.

I note that there was an identical question with no replies in oz-users: http://sourceforge.net/mailarchive/message...?msg_id=7123539

Going on from this, does anyone know how the Sharp remote control headphones are/could be handled?

Cheers,


Si

[lardman]

bump.

After seeing this page: http://www.areanine.gr.jp/~nyano/cerh1pad.html and its explanation of how the Sharp remote control works - 4th poll on headphone jack, various resitances trigger different keypresses - I started wondering about this again.

I can order the bits to make a Sharp style remote (though I'm not sure it will work with OZ anyway - I have a feeling it won't), but even more interesting would be to get something like a gen2 iPOD remote working (or something similar - 4 poll 3.5mm jack plug).

Now this would require the implementation of the particular protocol which the remote expects, and it's generally more than just a resistance change.

My question (same as before) is how is this resistance change mapped to a keypress? Is this a fixed hardware function (in which case I'll give up on getting a more complicated remote to work), or is it part of the kernel? How can this 4th poll be accessed programatically?

Cheers,


Si

[omega]

i think that the fourth pole is read by a simple 3bit ADC... sorry i can't be more help than this.

[lardman]

No that is useful, I don't suppose you happen to know whether this output can be driven too? Anbd how the adc data is accessed? Is it linked directly into the keyboard hardware/firmware or is it read by the kernel (I'll have to do some trawling).

If it's read (and even written to) by the kernel then it might be possible to get a remote display to work!

However I suppose I am really stuck with the voltages it uses as inputs (due to the 3bit ADC - not much more scope there). This is not really a major issue as I can always remap the keys it simulates so that I can try a differently setup remote (like some of the Sharp MD ones which operate in the same way, but with different keys and resitances, using an adaptor to move the exterior pins to the 4th poll, etc.).

Must check the resitances though to make sure I come out with the right values....

Out of interest, where did you pick up that little nugget of info?

Thanks Omega,


Si

[lardman]

Anyone know why the resistances (and therefore I assume the voltages which will be detected) are not linearly spaced for the Sharp remote? Obviously there are problems with getting resistors and trying to do it as cheaply as possible but these resitances are really rather different:

Play - 120 Ohm
Stop - 360 Ohm
Prev - 690 Ohm
Next - 1310 Ohm
Vol+ - 2510 Ohm
Vol- - 6410 Ohm

It's almost as if they double (or nearish to that) for each step up.

Looking at one of the Sony remotes, each step is approximately equal in size.

More questions ;-). Anyone happen to know what the supply current is? Is this the right way to look at it? The current should be constant and the voltage drops depending on the resistance I assume, and this voltage is then measured.


Si

P.S. Beginning to think it might be less hassle to just reach into my pocket and buy a Sharp one :-)