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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

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.


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
> >
>