Re: Libusb-win32 code to control Ricoh Theta

Hi Kevin,
could you point me exactly to the source where you found
the line
int result = usb_control_msg(devHandle, 0x21, 9, 0x2, 0x0, (char*)buffer,
64, 100);

maybe the control code is wrong...

Greets Ekkehard


Kevin Cain wrote
> Hello, Ekkehard,
> 
> I had the same thought about using a USB 'sniffer' to see how PTP requests
> should be formed, but unfortunately Ricoh's PC software does not control
> the camera.  It mostly updates firmware -- and here is the log I recorded
> while updating firmware using USBTrace (similar to USBSnoop):
> www.insightdigital.org/Ricoh_Theta_Device_Log_USBTrace.html
> 
> The connection statistics with the device are here:
> www.insightdigital.org/Theta_log.html
> 
> I also tried the various permutations of buffer string length you
> suggested, to no avail.
> 
> Thanks again,
> 
> -Kevin
> 
> 
> On Mon, Jul 21, 2014 at 12:24 AM, Ekkehard <

> edomning@

> >
> wrote:
> 
>> Hi,
>> the trailing 0x00 was just a guess since often text strings are "zero
>> terminated". I dont have any closer information about what you are doing,
>> sorry.
>> If you have a sample program that can trigger the capture, you may try to
>> use "UsbSnoop" to see the data transmitted.
>>
>> http://sourceforge.net/projects/usbsnoop/
>>
>> Best regards
>> Ekkehard
>>
>>
>> Kevin Cain wrote
>> > Thank you for your suggestions, Ekkehard,
>> >
>> > The 'memset(buffer, 0, 64)' command I send should fill the buffer with
>> '0'
>> > values, unless I'm making a fundamental error.  I will try your
>> variants.
>> >  Your suggestion that the camera may require a trailing '0' is
>> interesting
>> > -- I will try that as well, is there any reference to support that?
>> >
>> > I suspect my problem is in correctly deducing the parameters required
>> to
>> > send messages to the Theta via libusb, e.g.:
>> >
>> > *int usb_control_msg(usb_dev_handle *dev, int requesttype, int request,
>> > int
>> > value, int index, char *bytes, int size, int timeout);*
>> >
>> > I used USBTrace to detect the Ricoh-provided driver and uploaded the
>> > results here:
>> > www.insightdigital.org/Ricoh_Theta_Device_Log_USBTrace.html
>> >
>> > However, I don't yet see how to find the request details for the camera
>> in
>> > question.  I assume this comes up each time a programmer wishes to
>> control
>> > a new device with libusb -- are there any resources that might help me?
>> >
>> > Any help divining the correct syntax and message protocol parameters
>> would
>> > be wonderful.
>> >
>> > Thanks,
>> >
>> > -Kevin
>> >
>> >
>> > On Sun, Jul 20, 2014 at 3:25 AM, Ekkehard <
>>
>> > edomning@
>>
>> > >
>> > wrote:
>> >
>> >> Hi,
>> >> I have'nt done anything with the camara matter. From the programmers
>> >> view,
>> >> there is one thing I dont understand.
>> >> The used bytes the buffer are only  15 = "trigger-capture", but you
>> are
>> >> sending 64 bytes. If the command detection algo in the camera
>> validating
>> >> the
>> >> length of the buffer first, than the command will not be recognised.
>> >> So maybe you can try
>> >> int result = usb_control_msg(devHandle, 0x21, 9, 0x2, 0x0,
>> (char*)buffer,
>> >> 15, 100); if (result == 15) cout << "Successfully sent all bytes to
>> >> camera"
>> >> << endl;
>> >> or, if the camera may expect one zero at the end of the command
>> >> int result = usb_control_msg(devHandle, 0x21, 9, 0x2, 0x0,
>> (char*)buffer,
>> >> 16, 100); if (result == 16) cout << "Successfully sent all bytes to
>> >> camera"
>> >> << endl;
>> >>
>> >> A minor thing, as far as I know there is no need to claim the
>> interface
>> >> since the control mesaages are not related to any interface.
>> >>
>> >> Best regards
>> >> Ekkehard
>> >>
>> >>





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