Re: [gentoo-embedded] serial port handling question

[Daniel Stonier <d.stonier@gmail.com>]

I've never actually used the RTS on - always had it off. But just in
case you didn't find the details there's a setting in the termios
options structure for rts - have you tried that?

'man termios' - look for CRTSCTS.

I usually use a bit of code to set the flag off for my connections:

*******************************

termios options;
// Disable Flow control
#if defined(CRTSCTS)
    options.c_cflag &= ~CRTSCTS; // Disable hardware flow control (old)
#elif defined (CNEW_RTSCTS)
    options.c_cflag &= ~CNEW_RTSCTS; // Disable hardware flow control (new)
#endif
tcsetattr(file_descriptor,TCSAFLUSH,&options);

*******************************

Above, file_descriptor is the handle you get back from the previously
called open(...).

2010/1/14 David Relson <relson@osagesoftware.com>
>
> G'day,
>
> I'm porting some old DOS code to Linux for a medical device that is
> being upgraded.  Among other goodies, it has a sensor that sends data at
> 115KB to an onboard NS16550A (or equivalent).
>
> The sensor is controlled (in part) by setting RTS on and off. I looked
> high and low (pun intended) for an ioctl or similar call that would
> allow this level of control and couldn't find anything. I finally ended
> up using the ollowing lines of code:
>
>  outb(inportb(MCR) |  0x02, MCR);  //DTR,RTS=ON
>  outb(inportb(MCR) & ~0x02, MCR);  //DTR=ON,RTS=OFF
>
> Directly tweaking the I/O port runs against the grain, but it's the
> only thing I've found that works.
>
> Is there a better way to control the chip?
>
> Regards,
>
> David
>



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