David Woolley wrote:
In article <[EMAIL PROTECTED]>,
[EMAIL PROTECTED] (Torsten Krieger) wrote:
it seems to receive the DFC signal from Mainflingen correctly. I do not know
much of the receiver Hardware since it is proprietary and not well
documented, I only know that it receives the raw serial signal with 50 baud.
If it is interfacing at 50 bits per second through a UART (the actual
signal is 1 baud), the receiver's baseband processing is trivial and
you are processing the raw baseband signal with only low pass filtering
applied. The internals may not be published, but there are not exactly
any trade secrets in such a receiver.
The 50 baud serial interface is a hack in ntpd which makes use of the
error behaviour of UARTs when presented with the raw DCF signal.
The signal is not being processed as a proper aynchronous serial signal
and things like UART parity and framing errors do not have their standard
meanings, so would not be presented as such in error messages.
You still pretend that the pulse is a StartBit, Some LowBits, after that
Some HighBits,... and try to receive it with 50 (or 25 Baud) 8Bits/char ..
With 50 Baud there is a chance you get a framing error instead of 0x00
for the long pulse.
I tried that ~8/9years ago, but the UART processor on the MVME167 Board did
not support Baudrates below 100 Baud ;-(. in the end this inability was
beneficial. I put the DCF Signal Status in the housekeeping area of my
10ms Dataframes. better timing information than pushing it through software
first.
uwe
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