Astan Chee schrieb:
Diez B. Roggisch wrote:
Astan Chee wrote:
Hi,
Im trying to write a program for my USB device and I'm thinking of using
python to do this. The USB device is of my own making and it is
activated when one of the two data pins of the USB is given about 5V (or
similar to whatever the power pin is getting). Now I'm confused to if
the software to activate this can actually be written and how do I do
it? Any examples? I've seen pyUSB but it doesn't give me control over
the hardware and how much power is going through the data pins.
Unless I'm not getting something here.
Hi,
Thanks for all the responses but I forgot to mention that I have very
little hardware understanding (at least in english) and the device
itself it very simple and only needs about 5V power to be active. The
problem here is that I want to control when the device is active using a
computer so I thought USB might be a good choice since its simple (but
didn't turn out to be). I'm open to any other suggestions on how I might
achieve this hardware and software-wise (as in what interface should I
use, etc). Also I'm trying to stay away from (complex) micro controllers.
Any ideas?
Others suggested the parallel port. It is the natural choice for such
things, with two caveats:
- it is legacy, and thus often not available on modern hardware,
especially on mobile ones. So if you want it be prepared to additionally
buy a usb2parallel-adapter.
- it's electrical specs aren't as robust I fear. USB allos up to 500mA
to be drawn, and shouldn't break if you try more & fail (albeit, that
might be something that isn't true all the time). So you can draw quite
a bit of current from it (the stupid USB-cup-warmers are an example of
that). I have often had broken parallel-ports, and I think the reason is
that they *ARE NOT* specified to drive anything - they only provide
low-current control-lines. So whatever you design, you need a second
power-source then.
All in all, using a USB-controller is IMHO the best solution. The
AT90USBKey is a low-cost evaluation-board. ATMEL provides quite a bit of
example-code, and there is other FOSS available.
I have to admit though that the whole USB-topic isn't the easiest thing.
Diez
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