Mac Forum / Programming / Mac Programming / January 2006

Hi,

I am developing a non standard (i.e. non mouse keyboard type) HID
device to act as a interface between the Microchip 2550 PIC and a Mac
running OS-X (10.3.9). I have managed to develop a HID app working
under Windows OS, but I'm having trouble with the Mac implementation.

The Mac sees and reports the device correctly - an 'ioreg' listing
shows that all the parameters are as expected. The only exception is
the element list which seems to be huge and largely composed of element
params which are a little odd, however, I've seen a similar list on the
keyboard so I'm not sure how unusual this is.

I have several different samples of code. I can't get past SetConfig in
any of them. The device seems to open okay and returns the expected
configuration from the GetConfig descriptor with the exception of
wTotalLength  which seems  to have a size of 10496 instead of the
expected 87 (PC value) ( is this something to do with the massive
element list?).

I have tried implementing a codeless kext in case the system is
hijacking the device - however
a) I can open it,
b) behavior with and without the kext seems identical,

Since I am not a Mac programmer, though, it is possible that I may have
missed something in the kext.

I have also looked at methods employing cookies and queues but have got
no further.

I'd be very grateful if someone would HELP me on this problem...  I
seem to be going round in circles and can't seem to figure out how Mac
implements HID.

Thanks for your help.  Greatly appreciated!

Gary Ireland