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DCC Serial Decoding - Stretched Zeros

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DCC Serial Decoding - Stretched Zeros

Postby ddmzschultz » Wed Nov 29, 2017 2:58 pm

Hello,

I'm creating a pseudo command station and have the need to occasionally send stretched zero's. I'm following the DCC standards for this and I'm well within the 9900 uS limit.
What I've noticed is, if the message is sent without a stretched zero, the Pico Scope recognizes the message and displays the packet information within the waveform capture. But if the same message is sent with a stretched zero, the Pico Scope doesn't recognize the message and the whole waveform capture is lost. It doesn't display any of the packet information for any of the messages within that waveform capture. It appears to be confused by a stretched zero.
The sound card I'm sending the message to responds to both types of messages without a problem.

Has anybody else noticed this? Am I missing something?

Here's a screen shot with a stretched zero. The stretched zero is placed just after the preamble and before the address byte. The message just prior is the same message without a stretched zero.
DCC with Stretched Zero.JPG


Pico Scope: 2205 MSO
Software: 6.12.9

Thanks,
Dave
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Re: DCC Serial Decoding - Stretched Zeros

Postby Hitesh » Thu Nov 30, 2017 9:17 am

Hi Dave,

Is this from the extended packet format?

Could you please send a psdata file to support@picotech.com and we will investigate further.

Thanks,
Hitesh

Technical Support Engineer
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Re: DCC Serial Decoding - Stretched Zeros

Postby ddmzschultz » Thu Nov 30, 2017 1:55 pm

Yes, it's falls into the category of an extended packet format, but doesn't follow the DCC standards exactly. It's a message to change the master volume level. More of a story to this, but probably not relevant to this post? Let me know if you need more details and I'll send you an email.

Email with the psdata file on it's way shortly.

Thanks,
Dave
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Re: DCC Serial Decoding - Stretched Zeros

Postby Hitesh » Thu Dec 07, 2017 9:23 am

Hi Dave,

Please do send details to our support address. I would be happy to take a look and pass on the information to the Development Team.

Regards,
Hitesh

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