Re: [Pyusb-users] From libusbJava to pyusb

[Henning S. <h.s...@go...>]

Hi there,

actually i do not really know what that value stands for. In the libUsbJava doc 
(found here:http://libusbjava.sourceforge.net/wp/res/doc/ch/ntb/usb/LibusbJava.html#usb_control_msg%28long,%20int,%20int,%20int,%20int,%20byte[],%20int,%20int%29 )  
it is named "value" - well, got no idea what it does mean. 

'0x03 << 8 | var' means :0x08 shift by 8,  bitwise or var'

Does it help?

Greetings from Germany,

Henning



Am 18.01.2010 um 00:25 schrieb Wander Lairson:

> What does this expression mean: (0x03 << 8) | var ? I could not see it
> in the Python code...
> 
> Wander
> 
> 2010/1/17 Henning Spille <h.s...@go...>:
>> Hi there,
>> 
>> i'm trying to use this multi-plug (http://www.nw-s.net/images/sispm.jpg) with pyusb. I already used it form libusbJava which is based on the libusb from linux.
>> As it was no problem for me to get it working in java, i'm struggling with python. Well, i'm new to python (actually these are my first few lines of code) but i guessed it is more an pyusb related problem - caused by me.
>> 
>> I hoped i could convert (manually for sure) the code from libusbJava to pyusb, but it does not work - yet. I attached some lines of code, dmesg output and lsusb --verbose info, but i don't know if it is necessary. Please can someone have a look at the controlMsg translation:
>> 
>> Java Code:
>> 
>> int reqtype = 0x21;
>> // USB_DIR_OUT + USB_TYPE_CLASS +
>> // USB_RECIP_INTERFACE /*request type*/
>> int request = 0x09; // writing
>> byte var = (byte) (3 * plugNumber);
>> int index = 0;
>> byte _on = 0x03;
>> byte _off = 0x00;
>> switchTo = _on;
>> byte buffer[] = { var, switchTo };
>> int timeout = 250;
>> int size = 2;
>> if (LibusbJava.usb_control_msg(handle, reqtype, request, (0x03 << 8)
>>                                | var, index, buffer, size, timeout) < 0)  .....
>> 
>> My pyUsb Translation:
>> 
>> 
>> on = 0x03
>> off = 0x00
>> timeout = 250
>> try:
>>   print "Trying to switch"
>>   var = (3 * plugNumber)
>>   reqBuffer = [0] * 2
>>   reqBuffer[0] = var
>>   reqBuffer[1] = off
>>   print "Bytes to write: " + str(reqBuffer)
>>   written = handle.controlMsg(0x21, 0x09, reqBuffer,  value=0, index=0, timeout=250)
>>   print "Bytes written: " + str(written)
>> except Exception, err:
>>   print >> sys.stderr, err
>>   handle, device = None, None
>> 
>> 
>> 
>> The code works, no error in dmesg or elsewhere, but nothing happends at the device - so i guess there is something wrong somewhere. Can i somehow debug the communication?
>> 
>> Would be nice if someone has some minutes to help me,
>> 
>> Regards,
>> 
>> Henning
>> ------------------------------------------------------------------------------
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> 
> ------------------------------------------------------------------------------
> Throughout its 18-year history, RSA Conference consistently attracts the
> world's best and brightest in the field, creating opportunities for Conference
> attendees to learn about information security's most important issues through
> interactions with peers, luminaries and emerging and established companies.
> http://p.sf.net/sfu/rsaconf-dev2dev
> _______________________________________________
> Pyusb-users mailing list
> Pyu...@li...
> https://lists.sourceforge.net/lists/listinfo/pyusb-users