Duplicate console output to a RS232C and keep keyb where it is

Duplicate console output to a RS232C and keep keyb where it is

[Frank Torres]

How do I make Linux to use the serial port RS232C as console and get the
keyb entry from the normal console?

The RS232C is a serial port with 12V and there I have a BA63 20x4 display
connected. (info worldwide)
It is setted with the right speed, parity, etc. I use echo whatever
>/dev/ttyS2 and it works.
If I use the command line parameter everybody says:  (odd and 8 data bits is
what I use)
            serial=2,9600o8
            console=ttyS2,9600o8 console=tty0
it shows the kernel messages in tty0 and it also sends it to the serial port
(of course, but without configuring it, though, almost illegible) at the
point of starting init, it stops the output.

If I swap the consoles (console=tty0 console=ttyS2,9600o8) it sends the
kernel messages to both, the tty0 and the ttySn, but when init starts, it
begins to send the Welcome... adn the Press I to enter... messages
repetedely each time further one from another. Seldom it continues executing
rc.sysinit processes, but it never comes to the end. I check it by
connecting the serial output to a serial input in a PC also running Linux
and using cat /dev/ttyS0.

I also used the line s0:1234:respawn .... at inittab,   but it creates a new
line for loggin where you say it to do it. If I dont change lilo.conf but
only inittab, I can see the loggin message. I don't want that. I just want
it to get se loggin from the console I'm working with.

What I expect it to obtain all the console output through the serial port
and the input through my keyboard using any of the virual consoles (let's
say tty1), not comming from serial. Is there any way to do that?

Thanx from advance. Frank.

Re: Duplicate console output to a RS232C and keep keyb where it is

[Richard B. Johnson]

On Fri, 3 Aug 2001, Frank Torres wrote:
> 
> The RS232C is a serial port with 12V and there I have a BA63 20x4 display
> connected. (info worldwide)
> It is setted with the right speed, parity, etc. I use echo whatever
> >/dev/ttyS2 and it works.

It has probably been set okay after boot by `setserial` in some boot 
script.

> If I use the command line parameter everybody says:  (odd and 8 data bits is
> what I use)
>             serial=2,9600o8
>             console=ttyS2,9600o8 console=tty0

This is not valid. You cannot reasonably have parity and 8 bits. One
of them has to go. Either use 8 bits and no parity or 7 bits with
parity.

This is because there are 10 bits/baud. The "stop" bit is a timing
interval equal to one of these bits, between characters. Therefore, you
can have many stop bits, this just spaces the characters.


Cheers,
Dick Johnson

Penguin : Linux version 2.4.1 on an i686 machine (799.53 BogoMips).

    I was going to compile a list of innovations that could be
    attributed to Microsoft. Once I realized that Ctrl-Alt-Del
    was handled in the BIOS, I found that there aren't any.

Re: Duplicate console output to a RS232C and keep keyb where it is

[Frank Torres]

> On Fri, 3 Aug 2001, Frank Torres wrote:
> >
> > The RS232C is a serial port with 12V and there I have a BA63 20x4
display
> > connected. (info worldwide). It is setted with the right speed, parity,
etc. I use echo whatever
> > >/dev/ttyS2 and it works.
>
> It has probably been set okay after boot by `setserial` in some boot
> script.
>
> > If I use the command line parameter everybody says:  (odd and 8 data
bits is
> > what I use)
> >             serial=2,9600o8   and     console=ttyS2,9600o8 console=tty0
>
> This is not valid. You cannot reasonably have parity and 8 bits. One
> of them has to go. Either use 8 bits and no parity or 7 bits with
> parity.
>
> This is because there are 10 bits/baud. The "stop" bit is a timing
> interval equal to one of these bits, between characters. Therefore, you
> can have many stop bits, this just spaces the characters.

Richard:
I must tell you I am the one who sets the speed, IRQ and the rest of the
parameters of the serial port in an /etc/rc.serial built by me only with the
settings I need. The original rc.serial was producing some error when
executed by rc.sysinit (kern. 2.4.2-2)
I have to configure ttyS2 with both, setserial and stty, 'cause of the
parity and the stop bit, etc.
I tested the following configurations:
    8, no parity, stop b.
    8, no parity, no stop b.
    7, parity on, parity odd, stop b.
    7, no parity, no stop b.
All showed wrong or no characters in the display. It only worked with 8,
parity on, parity odd, stop b. (also with no stop b.)
The Linux is installed in a Beetle/M POS.
Perhaps it can't be done? I mean to obtain the video through the serial port
without modifying the normal keyb entry?
Thanx

Re: Duplicate console output to a RS232C and keep keyb where it is

[Richard B. Johnson]

On Fri, 3 Aug 2001, Frank Torres wrote:
> 
> Richard:
> I must tell you I am the one who sets the speed, IRQ and the rest of the
> parameters of the serial port in an /etc/rc.serial built by me only with the
> settings I need. The original rc.serial was producing some error when
> executed by rc.sysinit (kern. 2.4.2-2)
> I have to configure ttyS2 with both, setserial and stty, 'cause of the
> parity and the stop bit, etc.
> I tested the following configurations:
>     8, no parity, stop b.
>     8, no parity, no stop b.
>     7, parity on, parity odd, stop b.
>     7, no parity, no stop b.
> All showed wrong or no characters in the display. It only worked with 8,
> parity on, parity odd, stop b. (also with no stop b.)
> The Linux is installed in a Beetle/M POS.
> Perhaps it can't be done? I mean to obtain the video through the serial port
> without modifying the normal keyb entry?
> Thanx
> 

This works fine here (in /etc/lilo.conf):

 append  = "console=ttyS1,9600"       # RS-232C output
 append  = "console=null"             # (no log output)


Cheers,
Dick Johnson

Penguin : Linux version 2.4.1 on an i686 machine (799.53 BogoMips).

    I was going to compile a list of innovations that could be
    attributed to Microsoft. Once I realized that Ctrl-Alt-Del
    was handled in the BIOS, I found that there aren't any.

Re: Duplicate console output to a RS232C and keep keyb where it is

[Russell King]

On Fri, Aug 03, 2001 at 04:01:28PM +0200, Frank Torres wrote:
> > This is not valid. You cannot reasonably have parity and 8 bits. One
> > of them has to go. Either use 8 bits and no parity or 7 bits with
> > parity.

All standard 16550 family ports support 8 bits _and_ parity.  Ancient
serial ports did have a restriction, but that restriction is no more.

> All showed wrong or no characters in the display. It only worked with 8,
> parity on, parity odd, stop b. (also with no stop b.)

You actually mean 2 stop bits.  (There is _always_ one stop bit).

I read your first mail, but couldn't really grasp the details of your
problem.

Are you trying to direct console _output_ to ttyS2 and the VGA card, yet
still accept input from the PS/2 keyboard?  And then when you try to set
this up, you get garbled characters via ttyS2?

--
Russell King (rmk@arm.linux.org.uk)                The developer of ARM Linux
             http://www.arm.linux.org.uk/personal/aboutme.html

Re: Duplicate console output to a RS232C and keep keyb where it is

[Frank Torres]

> On Fri, Aug 03, 2001 at 04:01:28PM +0200, Frank Torres wrote:
> > > This is not valid. You cannot reasonably have parity and 8 bits. One
> > > of them has to go. Either use 8 bits and no parity or 7 bits with
> > > parity.
>
> All standard 16550 family ports support 8 bits _and_ parity.  Ancient
> serial ports did have a restriction, but that restriction is no more.
>
> > All showed wrong or no characters in the display. It only worked with 8,
> > parity on, parity odd, stop b. (also with no stop b.)
>
> You actually mean 2 stop bits.  (There is _always_ one stop bit).
>
> I read your first mail, but couldn't really grasp the details of your
> problem.
>
> Are you trying to direct console _output_ to ttyS2 and the VGA card, yet
> still accept input from the PS/2 keyboard?  And then when you try to set
> this up, you get garbled characters via ttyS2?

Smthng like that.
Yes, I'm trying to direct console output to ttyS2 and to the VGA card at the
same time.
I don't care if I have to direct it only to ttyS2, but I need to have the
input from
the PS/2 keyboard. When I use the line
                s2:2345:respawn ....
in inittab, it sends a login prompt to the display connected to ttyS2,
different console than
that on tty0, therefore, obtaining the keyboard input from PS/2 only for
tty0.
If I use the command append="console=ttyS2,9600 ...." in lilo.conf it
happens what I explained
in the first mail. If U want to, I can send you a mail with the kernel and
init messages I got
connecting another serial port to ttyS2 and saving the data.
I've seen everywhere it should be as simple as redirecting the output with
the "console" command.
But it doesn't continue working alright after the Welcome message. ¿?

Frank Torres   (34) 94 439 6261
Ingecom, Máximo Aguirre 18 Bis
Bilbao, 48011, Spain.

Re: Duplicate console output to a RS232C and keep keyb where it is

[Richard B. Johnson]

On Mon, 6 Aug 2001, Frank Torres wrote:

> 
> > On Fri, Aug 03, 2001 at 04:01:28PM +0200, Frank Torres wrote:
> > > > This is not valid. You cannot reasonably have parity and 8 bits. One
> > > > of them has to go. Either use 8 bits and no parity or 7 bits with
> > > > parity.
> >
> > All standard 16550 family ports support 8 bits _and_ parity.  Ancient
> > serial ports did have a restriction, but that restriction is no more.
> >

He said that he was connecting to a RS232C __terminal__. The fact that
a device (like the 8250x/16550) can be used for non-standard serial
communications is moot if you are not connecting to another 8250x/16550.
And, somebody who has "been doing it for 40 years", as was stated
in one response, should know that.

The RS-232C standard does not provide 8 bits at the same time parity
us enabled. The fact that you "can do it" with certain devices says
nothing for the standard. In fact, to help "fix" communications
problems caused by non-standard hookups, "ISTRIP" was provided in Unix
(and Linux), to strip off the parity bit that shouldn't be there anyway.
It occurs when there is a 7-bit with parity terminal talking to a 8-bit,
no parity host. If you are connecting to a terminal, and have some
communications problems, it's best to feed it standard stuff to start.

The current problem:
During the console initialization sequence, its speed gets set to
38400 baud. This means nothing to a virtual terminal. However, if
the attached RS-232C termional is also being set to the same speed,
this could explain the garbage characters.

So I suggest that Frank set his terminal to 38400 baud and see if
the problems disappear.


Cheers,
Dick Johnson

Penguin : Linux version 2.4.1 on an i686 machine (799.53 BogoMips).

    I was going to compile a list of innovations that could be
    attributed to Microsoft. Once I realized that Ctrl-Alt-Del
    was handled in the BIOS, I found that there aren't any.

Re: Duplicate console output to a RS232C and keep keyb where it is

[Frank Torres]

> On Mon, 6 Aug 2001, Frank Torres wrote:
>
> >
> > > On Fri, Aug 03, 2001 at 04:01:28PM +0200, Frank Torres wrote:
> > > > > This is not valid. You cannot reasonably have parity and 8 bits.
One
> > > > > of them has to go. Either use 8 bits and no parity or 7 bits with
> > > > > parity.
> > >
> > > All standard 16550 family ports support 8 bits _and_ parity.  Ancient
> > > serial ports did have a restriction, but that restriction is no more.
> > >
>
> The current problem:
> During the console initialization sequence, its speed gets set to
> 38400 baud. This means nothing to a virtual terminal. However, if
> the attached RS-232C termional is also being set to the same speed,
> this could explain the garbage characters.
>
> So I suggest that Frank set his terminal to 38400 baud and see if
> the problems disappear.
>

I tried it out since the beginning Dick, but the display is
hardware-configured to its max. speed (9600) So if I'd like to change the
speed to a lower one I'd have to take a soldering iron and change the hard
way. I could,  but I'm obtaining the right characters at the display after
writing an rc.serial with

    setserial /dev/ttyS2 UART 16550A IRQ 10 spd_cust divisor 12
    stty -F /dev/ttyS2 speed 9600 parenb parodd cs8 cstopb -crtscts

I don't care if I don't see the kernel messages. When rc.sysinit starts
through init it calls rc.serial and configure the port. The problem is that
I can't come to that point.. The moment rc.sysinit shows the message, it
falls into a loop showing the message again and again. I've saved that
output. If you want to, I can send U the file.

I just want to change the output to the serial port, but not the input.

inittab creates another prompt for login, that's not useful for me unless I
can tell it to get the input from keyboard.

I've been trying some other choices. I've read that when Linux starts it
uses the first display available. If it doesn't find one, it uses the first
serial port, thus, ttyS0. But ttyS0 is a RC-232 and I need RC-232Cs to feed
the display. So I swapped the major of ttyS0 and ttyS2, removed the display
card and restarted the system, but when the kernel starts, I can't see
nothing there. So I restored everything.
I'm trying desperate ways. Have U noticed it? :)

Greatfully, frank.

Re: Duplicate console output to a RS232C and keep keyb where it is

[J. Dow]

From: "Richard B. Johnson" <root@chaos.analogic.com>

> On Fri, 3 Aug 2001, Frank Torres wrote:
> >
> > The RS232C is a serial port with 12V and there I have a BA63 20x4 display
> > connected. (info worldwide)
> > It is setted with the right speed, parity, etc. I use echo whatever
> > >/dev/ttyS2 and it works.
>
> It has probably been set okay after boot by `setserial` in some boot
> script.
>
> > If I use the command line parameter everybody says:  (odd and 8 data bits is
> > what I use)
> >             serial=2,9600o8
> >             console=ttyS2,9600o8 console=tty0
>
> This is not valid. You cannot reasonably have parity and 8 bits. One
> of them has to go. Either use 8 bits and no parity or 7 bits with
> parity.
>
> This is because there are 10 bits/baud. The "stop" bit is a timing
> interval equal to one of these bits, between characters. Therefore, you
> can have many stop bits, this just spaces the characters.

Dick Johnson, that is utter nonsense. I have applications that use 8 bits,
even parity, and two stop bits. I have applications that use 7 bits no
parity and to stop bits.

Nor are there 10 buts/baud on an RS-232 port. Barring using BAUDOT protocols
the baud and bit rate of an RS-232 port are the same number. When you get
into complex signaling protocols such as are used in MODEMs you can get
multiple bits sent within a signal protocol interval. The latter is called
the baud (not baud rate) of the link. It is not uncommon to have 2400 baud
or signaling intervals per second and have each of these intervals encode
say 16 bits worth of data. Then you have to consider the error correcting
and other protocols that may be placed on the raw bits transmitted each
baud. Nonetheless, none of this applies to RS-232.

{^_^}    Joanne "Been doing this for nearly 40 years" Dow