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USB HID Get Report Descriptor failing.

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Dany
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2019/05/19 12:25:48 (permalink)
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USB HID Get Report Descriptor failing.

Hi, I am building a simple USB HID host with the P24FJ64GB002 and apparently I am not capable of reading in the device's HID Report Descriptor. All other descriptors give no problem, including the configuration descriptor which includes the HID descriptor which states a report descriptor size of 54dec (36 hex).
 
This is the USB setup command I use:
81060022 00003600
81 = STD_INTERFACE_TO HOST
06 = GET_DESCRIPTOR
22 = REPORT_DESCRIPTOR
36 = Report length.
 
Every time I issue that setup command with a read afterwards (exactly as I do with other descriptors) the nr of returned bytes is zero...
 
Anyone an idea?
Thanks in advance!

Kind regards,
Dany
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2 Replies Related Threads

    Dany
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    Re: USB HID Get Report Descriptor failing. 2019/05/21 04:22:29 (permalink)
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    Hi, if I insert a small delay (e.g. 1 ms) after filling the U1TOK regsiter before testing U1IR.trnIF then it seems to be OK.
    Since I can not explain why the delay make it Ok, my question still stands.
     
    Thanks in advance!

    Kind regards,
    Dany
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    LdB_ECM
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    Re: USB HID Get Report Descriptor failing. 2019/05/21 08:37:05 (permalink)
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    I suspect this is the same as another post dealing with this and it usually comes up on optical mice.
     
    If you don't move or do something on the mouse it returns the last report but gives you a count of zero.
    It's basically telling you nothing happened between polls.
     
    If you look at the report data I am sure you will find it simply matches the last one sent.
     
    So if you get a count of zero you can basically ignore it because nothing happened no button press, no movement.
    #3
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