[ECOS] Q: Serial Port Non-Echo?

Gary Thomas gthomas@redhat.com
Thu Jan 3 05:15:00 GMT 2002

On Thu, 2002-01-03 at 01:34, David Oberbeck wrote:
> Greetings all,
>    A (hopefully) quick question:
> 	How do I get a serial port to not echo bytes?
>    Background: iPAQ target, recent CVS version of eCos, gcc 3.0.3,
> Insight 5.1. We can receive just great using non-blocking reads, but
> the driver is echoing the bytes back before we 'see' them; we need to
> control what gets echoed back.
>    I looked at the Ref Manual, walked through parts of the code; I did
> find a no-echo flag in tty mode but not in raw ( e.g. cyg_io_read() )
> mode. There seems to be no config key (e.g. cyg_io_set_config() which
> has the right parms to read or set...
>    Am I missing something obvious? What's the best way around this?

The only place that "echo" happens is in the TTY driver(s) [either ttyXX
or termiosX].  You can control that behaviour with cyg_io_set_config()
or using the POSIX termios functions.

The lowest level read functions/driver (/dev/serX) only move data, there
is no interpretation and thus, no echoing.

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