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RE: Problem with Parallel port
Since my last mail I tried a few things more.
I could solve the boot up problem. (USB and Serial 1 should not be selected
I went through the component reference and could figure out that the Pin
number 1 is for sure the one with square soldering (so dumb I am)
Then I loaded the Etrax100parlcd drivers and tried to write on the port. The
echo "oPoPoP" > lcd worked (as it came back to prompt without giving any
Before connecting the LED's I thought of checking the voltage (in lack of a
CRO i used a digital multimeter :( )at each pin of x23. Here are the
findings which are different than expected
The pin number 10 (NC!), 11 (D4), 12 (GND!), 13(D5) and 15 (D6) are always
high (+3.3V). I was surprised to see the pin which is supposed to be ground
(12) is showing high voltage (even with a multimeter it should not show that
I could not figure out the reason for this. Could somebody help me out on
One more question - >
GPIOG refers to 32 bits GPIO I suppose the 32 bits are distributed as 8 PA,
8 PB, 8 LPT1 and8 LPT2.
And the sequence of the bits is PA,LPT1,LPT2,PB. Can somebody verify if my
interpretation is correct?
Behalf Of Alok Damle
Sent: Saturday, October 04, 2003 20:40
Subject: Problem with Parallel port
I am a newbie to device programming in Linux. I want to use the Parallel
port as IO port for glowing some LED's. I am trying to build the kernel with
Parallel port support but the kernel does not boots. I have tried following:
1. I tried installing the LCD drivers as directed in the
Device-drivers-HowTo page; but it also did not work. The Kernel did not boot
after I did ./ktest
2. I wrote a program to SET and clear bits on gpiog (without parallel port
support) using a program referred in
but I did not get any output (voltage) at the LPT pin header. I am using
Axis 82 MCM.
The method/assumptions I am carrying are:
A. I hope the pin which is soldered square in x23 is pin number 1.
B. I am measuring the output of the LPT header using Multimeter directly. Is
it fine or I require to use some different circuit. I tried to connect LED's
to connect to d0 and GND through a step-down resistor of 320 Ohms but the
LED did not glow for the set of terminals where multimeter is showing 3.3
I have gone through all the previous mails in the archive regarding Parallel
port. But I did not understand them much :(
I am also attaching the kernelconfig which had the parallel port setting and
which did not work.
Thanks in advance,