Lite5200 from RS232 to RS485

[Graham Williams]

I used tcgetattr and tcsetattr to set the termios settting like baud.  I
also had to recompile the kernel using make menuconfig and in MPC8xx CPM
Options-> I selected Use SCCx UART then Use SSC1 UART then selected PC15 for
RTS on SCC1 UART.  Make sure the second UART device (ttyS1) is in the /dev
directory and this should enable the RTS to work.  You can only use RTS with
the SCCs and NOT the SMCs.  Maybe the console ttyS0 is an SMC not an SCC at
least that is the way my eval board was setup. I hope this helps.

-----Original Message-----
From: saurosalomoni [mailto:saurosalomoni at bol.com.br]
Sent: Monday, June 14, 2004 4:54 AM
To: linuxppc-embedded
Cc: gwilliams
Subject: RE: Lite5200 from RS232 to RS485



> I did the same thing with an 860T.  All we needed was
the RTS pin

> (inverted).  We used the standard driver and
everything worked fine.  I did
> do a little ioctl stuff but no driver changes.


The point is that the driver I'm using does not support
ioctl. What I would like to know is how to set RTS
without using ioctl.
I know there is a way, but I couldn't find it yet...


>Here is the hello file I
> started with.   Good luck
>
> -----Original Message-----
> From: owner-linuxppc-embedded at lists.linuxppc.org
> [mailto:owner-linuxppc-embedded at lists.linuxppc.org] On
Behalf Of
> saurosalomoni
> Sent: Friday, June 11, 2004 6:35 AM
> To: linuxppc-embedded at lists.linuxppc.org
> Cc: iida at ztec.com.br

> Subject: Lite5200 from RS232 to RS485
>
>
> Hello.
>
> I need to switch between RS232 and RS485 in my Lite5200,
>  but I realized it's a little bit more dificult than I
> thought at first...
> Well,  as far as I'm concerned, I can do that just by
> controling the RTS pin of my ttyS0 device to activate
> the 485 module (is it 100% right?).
>
> I began trying to control it with TIOCMGET/TIOCMSET
> ioctl(),  but the driver does not support hardware
> handshake.. (tahnx,  Denk)
> So now I think I'll have to write a small driver that
> uses GPIO to handle the proper PSC register.
>
> MPC5200 Users Manual states that you can set/clear the
> RTS pin with bit 7 of the OutputPort 0 (op0, offset 0x3C).

>
> My questions:
> - Is this information I gathered correct?..
> - Which PSC register I need to use to control ttyS0?
> - If it's easyer to do it by extending an existing
> driver, wich file should I look for?

> - Is there any other way to accomplish that?
>
> Thanks in advance.

>


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