Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #28148

Re: Sending USB commands with Python

Path csiph.com!newsfeed.hal-mli.net!feeder3.hal-mli.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!newsfeed.xs4all.nl!newsfeed5.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail
Return-Path <cameron@cskk.homeip.net>
X-Original-To python-list@python.org
Delivered-To python-list@mail.python.org
X-Spam-Status OK 0.000
X-Spam-Evidence '*H*': 1.00; '*S*': 0.00; 'subject:Python': 0.05; 'binary': 0.05; 'sequences.': 0.07; 'utf-8': 0.07; 'encode': 0.09; 'encodes': 0.09; 'expected.': 0.09; 'skip:e 80': 0.09; 'such.': 0.09; 'cc:addr:python-list': 0.10; 'library': 0.15; '127': 0.16; 'adam': 0.16; 'ah,': 0.16; 'command)': 0.16; 'command:': 0.16; 'from:addr:cs': 0.16; 'from:addr:zip.com.au': 0.16; 'from:name:cameron simpson': 0.16; 'hex': 0.16; 'message- id:@cskk.homeip.net': 0.16; 'received:202.125.174': 0.16; 'received:202.125.174.133': 0.16; 'received:boardofstudies.nsw.edu.au': 0.16; 'received:cskk.homeip.net': 0.16; 'received:edu.au': 0.16; 'received:harvey.boardofstudies.nsw.edu.au': 0.16; 'received:homeip.net': 0.16; 'received:nsw.edu.au': 0.16; 'simpson': 0.16; 'translation': 0.16; 'wrote:': 0.17; 'byte': 0.17; 'bytes': 0.17; '>>>': 0.18; 'cheers,': 0.23; 'cc:2**0': 0.23; 'cc:no real name:2**0': 0.24; 'least': 0.25; 'cc:addr:python.org': 0.25; 'header:In-Reply-To:1': 0.25; 'header :User-Agent:1': 0.26; 'looks': 0.26; 'values': 0.26; 'all.': 0.28; 'trouble': 0.28; 'arthur': 0.29; 'concern': 0.29; 'i/o': 0.29; 'prints': 0.29; 'subject:Sending': 0.29; 'character': 0.29; '"the': 0.29; 'thursday,': 0.30; 'code': 0.31; 'getting': 0.33; '11,': 0.33; 'text,': 0.33; 'changed': 0.34; 'whatever': 0.35; 'but': 0.36; 'received:au': 0.36; 'subject:with': 0.36; 'charset :us-ascii': 0.36; 'does': 0.37; 'subject:: ': 0.38; 'instead': 0.39; 'short': 0.39; 'claim': 0.60; 'content-disposition:inline': 0.60; '30,': 0.62; 'more': 0.63; 'august': 0.66; 'million': 0.72; 'celebrated': 0.84; 'howard': 0.84; 'subject:commands': 0.84; 'dennis': 0.91; 'story,': 0.91
Date Fri, 31 Aug 2012 08:47:56 +1000
From Cameron Simpson <cs@zip.com.au>
To "Adam W." <AWasilenko@gmail.com>
Subject Re: Sending USB commands with Python
MIME-Version 1.0
Content-Type text/plain; charset=us-ascii
Content-Disposition inline
In-Reply-To <20c77648-7b1f-4a45-82de-c8721c834394@googlegroups.com>
User-Agent Mutt/1.5.21 (2010-09-15)
References <20c77648-7b1f-4a45-82de-c8721c834394@googlegroups.com>
Cc python-list@python.org
X-BeenThere python-list@python.org
X-Mailman-Version 2.1.12
Precedence list
List-Id General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe <http://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive <http://mail.python.org/pipermail/python-list>
List-Post <mailto:python-list@python.org>
List-Help <mailto:python-list-request@python.org?subject=help>
List-Subscribe <http://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups comp.lang.python
Message-ID <mailman.3992.1346366887.4697.python-list@python.org> (permalink)
Lines 32
NNTP-Posting-Host 2001:888:2000:d::a6
X-Trace 1346366887 news.xs4all.nl 6975 [2001:888:2000:d::a6]:55747
X-Complaints-To abuse@xs4all.nl
Xref csiph.com comp.lang.python:28148

Show key headers only | View raw

On 30Aug2012 05:51, Adam W. <AWasilenko@gmail.com> wrote:
| On Thursday, August 30, 2012 12:55:14 AM UTC-4, Dennis Lee Bieber wrote:
| > 	How many bytes did it claim to send?
|
| 11, which is what I expected.  But I changed the byte value to 16
| (because I was having trouble getting single digit hex values working
| in the command) and sent this command:
|
| >>> for x in range(0,500):
| 	ep.write(b'\x16\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF')
| 
| it respond with 500 17's and prints a black bar!  So it looks like whatever concern you had with using encode was coming to fruition.

Yeah. Try 'iso8859-1' instead of 'utf-8'. You want to be not translating
the byte values at all. UTF-8 encodes character values over 127 as multibyte
sequences. ISO8859-1 is a 256 code set that does no translation -
character codes in go directly to byte values out.

You're speaking a binary protocol, not text, so you want a one to one
mapping. Better still would be to be using a bytes I/O layer instead of
one with a text->byte translation; I do not know if the USB library
you're using offers such. So try 'iso8859-1'; at least the translation
is a no-op.

Cheers,
-- 
Cameron Simpson <cs@zip.com.au>

B1FF is an archetype, and all you're showing us is one of the more amusing of
his many instantiations.        - Howard E. Motteler <motteler@umbc.edu>
Ah, perhaps Arthur Clarke anticipated this in his celebrated short story,
"The Nine Million Names Of B1FF"? - Nosy <ataylor@nmsu.edu>

Back to comp.lang.python | Previous | Next — Previous in thread | Find similar | Unroll thread

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

csiph-web