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

Torsten Krieger Torsten.Krieger at krieger-mis.de
Sun Oct 15 11:28:09 UTC 2006


Hi Uwe,

I made a small c program which reads the serial port /dev/refclock-0
character by character, ntpd switched off. Shall I see one character by
second (second = 1/60 minute) 0xf0 for low bit and 0x00 for high bit? If
this should be the case then something went wrong with my serial interface.

Ciao,
Torsten

Uwe wrote:
>http://www.eecis.udel.edu/~mills/ntp/dcf77.html
>
>The DCF Signals is 1 pulse every 1 second. the 59th pulse is omitted to
>mark the minute transition.
>AAdditonal information is coded into the pulselength of the second pulses.
>0.1 sec for a low bit, 0.2sec for a high bit.
>
>on a 50Baud (0.02s/bit) serial line with inverted sense this is received as
>
>HHHHLLLLLHHHHHHHH	S=StartBit, s=StopBit(s)
>____S01234567s____  0xf0 for a low bit
>
>and
>
>HHHHLLLLLLLLLHHH
>____S01234567s____  0x00 for a high bit
>
>uwe

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