[ntp:questions] Re: ***SPAM*** AW: Re: AW: convert_rawdcf: parity check FAILED on my embedded Linux system

Frank Kardel kardel at acm.org
Sat Oct 14 09:17:56 UTC 2006


Torsten.Krieger at krieger-mis.de (Torsten Krieger) writes:

> Hi Frank,
>
> thank you for your help!
>
> It is not clear to me whether parity check shall be enabled or disabled!
> With stty -a /dev/refclock-0 I have the following output:
>
> [root at axis /]91# stty -a -F /dev/refclock-0
> speed 50 baud; rows 0; columns 0;
> intr = <undef>; quit = <undef>; erase = <undef>; kill = <undef>; eof =
> <undef>;
> eol = <undef>; eol2 = <undef>; start = <undef>; stop = <undef>; susp =
> <undef>;
> rprnt = <undef>; werase = <undef>; lnext = <undef>; flush = <undef>;
> min = 1; time = 0;
> -parenb -parodd cs8 -hupcl -cstopb cread clocal -crtscts
> -ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl -ixon
> -ixoff -iuclc -ixany -imaxbel
> -opost -olcuc -ocrnl -onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0
> vt0 ff0
> -isig -icanon -iexten -echo -echoe -echok -echonl -noflsh -xcase -tostop
> -echoprt -echoctl -echoke
>
> Is this a correct setting for the serial port?
>
fine - PARENB is disabled.

You usually should not have to fiddle with that, as the daemon code 
sets up the tty interface.

The parity message refers to a parity error in the transmitted
time code not in the characters received (each character is just
a single bit the the time code).

>>
> This has nothing to do with parity check on the serial port.
>
> The DCF77 signal transmits 3 parity bits in its data stream.
> This messages is generated when the check fails. This happens
> usually when the reception is sub-optimal and bit errors occur.
> Occasional errors are harmless.
>
> If this message is interfering with the opration of your embedded
> system you should only disable the output of the message - not the
> check.
>
Frank




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