[ntp:questions] Cheap ($29.90) GPS receiver

David J Taylor david-taylor at blueyonder.co.uk.invalid
Wed Apr 21 05:24:36 UTC 2010

"David Woolley" <> wrote in message 
news:hql5kh$2me$1 at news.eternal-september.org...
> The FIFO can be turned off (is off by default) on 16550s.  The basic 
> UART algorithm is:
> Sample at 16 times baud rate.
> On detecting a space, resample in 8 (maybe 7) clocks.  If still space, 
> start assembling character.
> Sample every 16 clocks until middle of stop bit.
> Interrrupt with either good or framing error status, depending whether 
> the last sample is mark or space.
> That means that for most of the time, the peak to peak receive jitter is 
> 1/(16 * baud rate).
> There will also be a jitter of this amount at the transmitter, as it 
> will start transmitting the next clock after the buffer is loaded.

It sounds like someone should buy one of these devices (get as a sample, 
or on sale-or-return?) and see what it actually does!  No point in me 
doing so, as I have neither the OS nor the willingness to pay the shipping 
charge out of the US (even if the firm supplies what they consider to be 
untrustworthy foreigners, like some US battery vendors).


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