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Re: Use of GPIOG driver on g8-g23




----- Original Message ----- 
From: "Jon Möller" <jon.moller@xxxxxxx.se>
To: <dev-etrax@xxxxxxx.com>
Sent: Tuesday, August 31, 2004 3:17 PM
Subject: Use of GPIOG driver on g8-g23


> Hello list,
>
>
>
> Thought this should be very easy but somehow I can't get it to work. I
must have missed something obvious and elementary.
>
> Despite being a complete beginner in both Linux environment and the ETRAX
chip I have managed to install, connect to, build test applications, build
the test LCD-driver, use the CGI support in the Boa server and flash the
devboard82 with all my stuff without problems. Or maybe I should correct
that to whenever I had a problem the simple answer was to find in previous
posting in this list.
>
>
>
> But now I seem to have problem with this simple GPIOG driver. I want to
control and set the bits on g8 through g23 (lp0 and lp1 data bits)
individually but I can't measure any changes on any of the pins with my
scope. I don't get any errors upon opening or writing to the port (gpio
driver ioctl's). I've tried setting directions, disabled other ports etc,
but still no change. I even looped the same output many times to see if
there was some life on the pins. The etrax100parlcd driver works fine though
(changed it to 2x16char instead of 4x20char LCD) and writes out whatever I
want on my LCD even though parport support is enabled (I want to have
support enabled for as may ports as possible, see below). None of the
previous posts in this list gave me hint of why I can't get it to work with
the GPIOG driver. Probably because it is something obvious I have missed =(
>
>
>
> My suspicions...
>
> 1. I have some wrong settings in menuconfig (I'm not so familiar with all
that stuff).
>
> 2. Pin 26 on x23 (LPT1). Should I do something with that pin and if so
exactly what?

Pin g5 controls the direction of the external buffer on LPT1 (lp0),
try changing it's state.

> 3. Sometimes I get pin 7 on x23 (LPT1, D2) set to high (3.3V) but I don't
know why and how it happens...(!?)

It's probably an input floating så you get whatever noise flying around?

> 4. What else have I missed or not aware of (I'm not a software guy
really)?


Best regards
/JOhan