[ECOS] Canonical tty (termios) and nonblocking

[ECOS] Canonical tty (termios) and nonblocking

[Rutger Hofman]

Good evening list,

I run into the following problem. I have a device that is attached to a 
serial port (a BlueTooth thingy).

This port is opened in my application as a file, /dev/ser0 or /dev/tty0 
or /dev/termios0 or /dev/... I want to control the line speed for the 
serial connection from the application, so I want to use tcsetattr or 
cfseti/ospeed. This interface only exists for termios devices 
("/dev/termios0"), as defined in 
packages/io/serial/current/src/common/termiostty.c

Now, this BlueTooth thingy talks to some other device, not a human. So 
the terminal should NOT be in canonical mode: no special handling of 
ERASE and KILL (though these can be disabled separately), and of course 
no buffering -- which /cannot/ be disabled separately. However, if I 
look at the code (above file, line 656-675 in CVS from a week ago), if 
the device is not canonical, receive is implemented as *nonblocking*.
This is emphatically not what I want, and I think blockingness should be
specified in another way, by using O_NONBLOCK or O_NDELAY as parameters 
for open(2).

Any ideas where my reasoning went astray, or how this can be fixed?

Greetings,

Rutger


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Re: [ECOS] Canonical tty (termios) and nonblocking

[Andrew Lunn]

On Thu, Jul 19, 2007 at 12:33:43AM +0200, Rutger Hofman wrote:
> Good evening list,
>
> I run into the following problem. I have a device that is attached to a 
> serial port (a BlueTooth thingy).
>
> This port is opened in my application as a file, /dev/ser0 or /dev/tty0 or 
> /dev/termios0 or /dev/... I want to control the line speed for the serial 
> connection from the application, so I want to use tcsetattr or 
> cfseti/ospeed. This interface only exists for termios devices 
> ("/dev/termios0"), as defined in 
> packages/io/serial/current/src/common/termiostty.c

There is an eCos way to set the line speed. Take a look at

cyg_io_set_config() and there should be a key to set the speed of the
device. You can apply this to the raw device.

        Andrew

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