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RE: Serial port config - kernel



I've resolved the issue I was having with the AXIS82 serial port and wish to
thank those who replied and offered advice.

My software had a timing issue (select() before a read()) - things were a
little too tight.

Forcing DTR high (all the time) had nothing to do with it.  At the time, as
this was the only difference I could see between a working and non-working
setup, it seemed like a good option to pursue.  Oh well.

Thanks again!

Mark Richards



> -----Original Message-----
> From: owner-dev-etrax@xxxxxxx.com
> [mailto:owner-dev-etrax@xxxxxxx.com] On Behalf Of Johan Adolfsson
> Sent: Thursday, July 08, 2004 14:45
> To: Mark Richards; 'Mikael Starvik'; 'dev-etrax'
> Subject: Re: Serial port config - kernel
>
>
>
> ----- Original Message -----
> From: "Mark Richards" <mark.richards@xxxxxxx.com>
> To: "'Mikael Starvik'" <starvik@xxxxxxx.com>; "'dev-etrax'"
> <dev-etrax@xxxxxxx.com>
> Sent: Thursday, July 08, 2004 5:10 PM
> Subject: RE: Serial port config - kernel
>
>
> > I carefully examined the differences between the ETRAX 82 and two
> > other PC's.
> >
> > RS-232 Voltage DTR RTS
> >
> > ETRAX +/- 7v LOW LOW
> >
> > PC +/- 10v HIGH HIGH
>
> Are you sure that you measured these values when the serial
> port is in the same state? When a serial port is opened the
> driver should set RTS and DTR to "active" which perhaps could
> explain the differences.
>
> > The Dallas DS-9097U requires RXD, TXD, GND, and DTR (HIGH)
> to operate
> > properly.  The Dallas spec for the DS-9097U (9 pin) says
> that it will
> > work from +/- 5v to +/- 12v for RS-232 signals, so the
> ETRAX seems to
> > fall into the correct range.
> >
> > Is there a way to force DTR HIGH in the ETRAX 82.  I think
> this may be
> > the problem.
>
> Either do the proper ioctl (TIOCMBIS or TIOCMBIC) with
> TIOCM_DTR flag set or depending on the serial port used
> change the default value of PA4 or PB4 by modifying
> CONFIG_ETRAX_DEF_R_PORT_PA_DATA=f0
> or
> CONFIG_ETRAX_DEF_R_PORT_PB_DATA=f3
> to value e0 or e3
> (Om not sure what you mean with HIGH/LOW so I'm not sure what
> value you
> want)
>
> and modify
> CONFIG_ETRAX_SER0_DTR_ON_PB_BIT=4
> or
> CONFIG_ETRAX_SER2_DTR_ON_PA_BIT=4
> to -1
> to disable the use of DTR from the serial driver.
>
> /Johan
>
> > Mark Richards
> >
> >
> >
> > > -----Original Message-----
> > > From: Mikael Starvik [mailto:mikael.starvik@xxxxxxx.com]
> > > Sent: Thursday, July 08, 2004 00:47
> > > To: 'Mark Richards'
> > > Subject: RE: Serial port config - kernel
> > >
> > >
> > > The hardware controls some pins on the serial port (TXD,
> RXD, RTS,
> > > CTS) while the rest (CD, RI, DTR, DSR) are handled by
> software. The
> > > pins handled bys software is connected to Port A or Port
> B (see e.g.
> > > http://developer.axis.com/doc/hardware/devboard_82/21232r1_sch
> > > ema.pdf).
> > >
> > > The following applies for devboard 82:
> > >
> > > ttyS0
> > >   DTR - PA4
> > >   RI - PA5
> > >   DSR - PA6
> > >   CD - PA7
> > > ttyS2
> > >   DTR - PB4
> > >   RI - PB5
> > >   DSR - PB6
> > >   CD - PB7
> > >
> > > /Mikael
> > >
> > > -----Original Message-----
> > > From: Mark Richards [mailto:mark.richards@xxxxxxx.com]
> > > Sent: Wednesday, July 07, 2004 10:29 PM
> > > To: Mikael Starvik
> > > Subject: RE: Serial port config - kernel
> > >
> > >
> > > Mikael,
> > >
> > > Thanks for the info.
> > >
> > > In the kernel configuration for each of the AXIS 82 serial ports
> > > (ttyS0-ttyS2), the DTR, RI, DSR, and CD options are
> provided for PA
> > > and PB. Since ttyS0 and ttyS2 don't come out on the 8 bit
> port, what
> > > purpose do these configuration setting serve?
> > >
> > > I'm scoping out the pins on a working system and will
> compare with
> > > the default settings on the AXIS 82.  I'm not fully
> certain what the
> > > DS9097-U requires.
> > >
> > >
> > > Mark Richards
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > From: owner-dev-etrax@xxxxxxx.com
> [mailto:owner-dev-etrax@xxxxxxx.com]
> > > > On Behalf Of Mikael
> Starvik
> > > > Sent: Wednesday, July 07, 2004 02:19
> > > > To: Mark Richards; dev-etrax
> > > > Subject: RE: Serial port config - kernel
> > > >
> > > >
> > > > Hi,
> > > >
> > > > >If I enable ttyS1 and disable ttyS2 and ttyS3, will ttyS1
> > > > appear on the
> > > > >second DB9 connector?
> > > >
> > > > No.
> > > >
> > > > >If not, is there a way in the kernel configuration to
> make it so?
> > > >
> > > > No
> > > >
> > > > >I know the meaning of DTR, RI, DSR, and CD, but what is PA
> > > > and PB?  Are
> > > > >these settings for the DB9 connecto
> > > >
> > > > PA and PB are two 8-bit ports on ETRAX. The default
> > > settings supplied
> > > > in the Axis 82 kernelconfig should be ok.
> > > >
> > > > >Should the DMA IN and DMA OUT be disabled?
> > > >
> > > > In all normal cases you should have DMA enabled.
> > > >
> > > > >I am using a simple Dallas 1-wire DS-9092 RS-232 to 1-wire
> > > > >adapter.  It works fine on a PC, but not on the AXIS 82.
> > > >
> > > > Doesn't work at all? Try connect only RX, TX and GND
> and see if it
> > > > works.
> > > >
> > > > Best Regards
> > > > /Mikael
> > > >
> > >
> >
> >
>
>