[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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
at together!)
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 suppose).

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?



-----Original Message-----
From: owner-dev-etrax@xxxxxxx.com]On">mailto:owner-dev-etrax@xxxxxxx.com]On
Behalf Of Alok Damle
Sent: Saturday, October 04, 2003 20:40
To: dev-etrax@xxxxxxx.com
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,