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Re: Sending USB commands with Python

Newsgroups comp.lang.python
Date 2012-08-29 16:45 -0700
References <eq3t38542luf3dmula4k92islpa9lh0opk@invalid.netcom.com> <20120829222932.GA18700@cskk.homeip.net> <mailman.3947.1346280975.4697.python-list@python.org>
Subject Re: Sending USB commands with Python
From "Adam W." <AWasilenko@gmail.com>
Message-ID <mailman.3950.1346283912.4697.python-list@python.org> (permalink)

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On Wednesday, August 29, 2012 6:56:16 PM UTC-4, Dennis Lee Bieber wrote:
>
> 	BUT you do give a possible clue. Is the OP using a 3.x Python where
> 
> strings are Unicode -- in which case the above may need to be explicitly
> 
> declared as a "byte string" rather than text (unicode) string.
> 

Huzzah!  I am indeed using 3.x, and slapping on an .encode('utf-8') made my printer try to spit paper at me! Progress.

Also, astute observation about the endpoint needing to be an input, with the following modification I get:

>>> ep.write('\x1BA'.encode('utf-8'))
2
>>> ep = usb.util.find_descriptor(
    intf,
    custom_match = \
    lambda e: \
        usb.util.endpoint_direction(e.bEndpointAddress) == \
        usb.util.ENDPOINT_IN
)
>>> ep.read(1)
array('B', [163])
>>> 

Anyone want to venture a guess on how I should interpret that?  It seems the [163] is the byte data the manual is talking about, but why is there a 'B' there?  If I put paper in it and try again I get: array('B', [3])

Thanks for all your help guys, just about ready to stared coding the fun part!

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Thread

Re: Sending USB commands with Python Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-29 18:56 -0400
  Re: Sending USB commands with Python "Adam W." <AWasilenko@gmail.com> - 2012-08-29 16:45 -0700
  Re: Sending USB commands with Python MRAB <python@mrabarnett.plus.com> - 2012-08-30 01:53 +0100
  Re: Sending USB commands with Python Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-29 22:07 -0400
    Re: Sending USB commands with Python Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-30 00:55 -0400
      Re: Sending USB commands with Python "Adam W." <AWasilenko@gmail.com> - 2012-08-30 05:51 -0700
        Re: Sending USB commands with Python Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-30 14:24 -0400
        Re: Sending USB commands with Python Cameron Simpson <cs@zip.com.au> - 2012-08-31 08:47 +1000

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