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Re: Problem with Parallel port
----- Original Message -----
From: "Alok Damle" <firstname.lastname@example.org>
Sent: Sunday, October 05, 2003 8:29 PM
Subject: 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
> 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.
> 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
> 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
> (12) is showing high voltage (even with a multimeter it should not show
> i suppose).
> I could not figure out the reason for this. Could somebody help me out on
Are you sure you have counted the pins correctly, that is:
If you counted it wrong, you would get what you see above.
To see the output you must have the output enable pin correctly
(you can watch it on pin 26 of X23)
> One more question - >
> GPIOG refers to 32 bits GPIO I suppose the 32 bits are distributed as 8
> 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?
No, it's not correct.
PA and PB is dedicated 8 bit ports on seperate devices.
Port G is the multiplexed pins used for various interfaces.
Se chapter 20.9 in the designers reference for details.
> -----Original Message-----
> From: email@example.com]On">mailto:firstname.lastname@example.org]On
> Behalf Of Alok Damle
> Sent: Saturday, October 04, 2003 20:40
> To: email@example.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
> Parallel port support but the kernel does not boots. I have tried
> 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
> 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.
> it fine or I require to use some different circuit. I tried to connect
> 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
> port. But I did not understand them much :(
> I am also attaching the kernelconfig which had the parallel port setting
> which did not work.
> Thanks in advance,