Serial decoding misses start bit after a few characters

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BramPeeters
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Joined: Fri Oct 14, 2016 11:37 am

Serial decoding misses start bit after a few characters

Post by BramPeeters » Tue Dec 19, 2017 1:53 pm

Hi,

I was trying too use serial decoding but the decoding is not really working well.
It seems to miss the start bit of the next character and then completely gets misaligned (see attachment where i measure length of the first missed start bit)
PicoScopeSerialDecoding.jpg
.
Looking at the timings, the bits are a 'bit' to short but not much (unfortunately it is a peripheral generating the stream so i cannot 'fix' that). But i get the impression from the visual representation that because the characters come right after each other, that the timing errors keep adding up till he looses track.
Ironically, it works better if my resolution decreases, eg 100ms/div works fine but 1ms/div and the decoding gets corrupted.

Version 6.12.9.2917.

Regards
Bram

Martyn
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Re: Serial decoding misses start bit after a few characters

Post by Martyn » Fri Dec 22, 2017 1:07 pm

There looks like plenty of dead time in the capture. If you change the timebase to 500usec/div or faster, and increase the sampling rate, does this improve the decoding ?
Martyn
Technical Support Manager

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