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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
> > >
> >
>
>