[visionegg] Re: parallel port 2nd
- From: Christoph Lehmann <lehmann@xxxxxxxxxxxx>
- To: visionegg@xxxxxxxxxxxxx
- Date: Mon, 03 Feb 2003 11:09:25 +0100
yes, even grounding it, yields in no change!
christoph
On Sat, 2003-02-01 at 04:19, Andrew Straw wrote:
> Have you tried grounding the pin (not just letting it float)? That may
> do the trick. I would try alternately grounding it and then giving it
> +5V and see if you can get the output to change.
>
> Cheers!
> Andrew
>
> On Saturday, February 1, 2003, at 01:39 AM, Christoph Lehmann wrote:
>
> > Hi Andrew
> >
> > I have some problems, which gets me crazy.....
> >
> > with the code:
> >
> >
> > input_value = 0
> > while (input_value == 0):
> > my_debug_msg.append('before<' + str(input_value) + '>lastimage
> > <'
> > + str(last_image) + '>')
> > input_value = raw_lpt_module.inp(0x379) & 0x20 #I use pin 12
> > my_debug_msg.append('after<' + str(input_value) + '>lastimage <'
> > + str(last_image) + '>')
> >
> > and nothing(!) on the LPT (open port) gives me (cycling trough the
> > whole
> > two times):
> >
> > before<0>lastimage <0>
> > after<32>lastimage <0>
> > before<0>lastimage <1>
> > after<32>lastimage <1>
> >
> > -> it seems that there is a logical 1 on the pin 12! why?
> >
> > thank you very much, Andrew, for a hint
> >
> > cheers
> > christoph
> >
> >
> > On Tue, 2002-12-17 at 18:07, Andrew Straw wrote:
> >> Hi Christoph,
> >>
> >> Your two questions about the parallel port are essentially the same.
> >> "inp()" returns a byte (well, actually it's a Python int, but it will
> >> always be 0-255). When you've pointed it to the parallel port like
> >> "inp(0x379)", 8 bits of the parallel port get stored in the return
> >> value. This happens according to the standard method for encoding
> >> multi-pin digital signals. In Python, this would be (obviously the
> >> system drivers don't run Python...)
> >>
> >> result = 0
> >> for n in range(8):
> >> result += bit[n]*(2**n)
> >>
> >> therefore to get bit[n], you want to do something like
> >>
> >> for n in range(8):
> >> bit[n] = result & 2**n
> >>
> >> So, if all you care about in your code is bit 4, you can just do bit4
> >> =
> >> result & 0x10. So, modify your code from
> >>> input_value = raw_lpt_module.inp(0x379)
> >>
> >> to
> >> input_value = raw_lpt_module.inp(0x379) & 0x10
> >>
> >> ======================================
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> > --
> > Christoph Lehmann
> > Department of Psychiatric Neurophysiology
> > University Hospital of Clinical Psychiatry
> > Waldau
> > CH-3000 Bern 60
> > Switzerland
> >
> > Phone: ++41 31 930 93 83
> > Mobile: ++41 31 570 28 00
> > Fax: ++41 31 930 99 61
> > Email: lehmann@xxxxxxxxxxxx
> > Web: http://www.puk.unibe.ch/cl/pn_ni_cv_cl.html
> >
> > ======================================
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> >
>
> ======================================
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--
Christoph Lehmann
Department of Psychiatric Neurophysiology
University Hospital of Clinical Psychiatry
Waldau
CH-3000 Bern 60
Switzerland
Phone: ++41 31 930 93 83
Mobile: ++41 31 570 28 00
Fax: ++41 31 930 99 61
Email: lehmann@xxxxxxxxxxxx
Web: http://www.puk.unibe.ch/cl/pn_ni_cv_cl.html
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