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Problem Changing Report Descriptor

Posted: Mon Jul 23, 2007 9:48 am
by H&Mcorp
I try to change some descrptor value in HIDkeys firmware ,
when we change some descriptor values like logical_maximum the device can not connect to pc . the message is " Device Can't start (code 10 ) "

we are using HID descriptor tool from to make Descriptor values.

Is there anywhere else to change when we change the report Descriptors ?
except reportBuffer I think .

Posted: Thu Jul 26, 2007 12:18 pm
by christian
Windows is very strict when it checks the consistency of report descriptors and whether the report complies to the descriptor.'s descriptor tool does not check the consistency of the descriptor at all. You can easily create descriptors which are rejected by Windows.

It's easiest to start with a descriptor which is known to work and modify it in small steps into the direction you want. This way you know WHICH modification caused the problems.

still have some problem

Posted: Sun Jul 29, 2007 12:02 pm
by H&Mcorp
thank you dear christian :

but our problem still remaining !

let me describe our problem :
we need to control windows media player with HID codes !
so , we need media play , pause , volume up & down ,.....
but no one of the HID codes from HID tables working properly !!!!!
in fact we can only see codes working from A to F24 from keyboard table !
that mean , we can only have correct codes from 4 to 115 from keyboard HID table , ( we used HIDKeys firmware for this porpuse )
we will thank you so much if you change codes for this purpose and send it to my email , because we try it so much but still no response from it , our mail address is : " "

Thank you for your helps in advance .

best regards

Posted: Mon Jul 30, 2007 4:19 pm
by christian
Have you checked whether Windows Media Player supports control through these keyboard extensions at all? These key codes may be filtered by the Windows kernel driver or they may be mapped to events which are ignored by Windows Media Player.

I have no experience with Windows myself, so I'm araid I can't help much more than that.

Posted: Wed Aug 08, 2007 11:18 pm
by Darwin
I think you need to add second descriptor in order to control the volume as shown in microsoft website.