Running VISA Serial at 460800

[ShotSimon]

I'm trying to run the Continuous Serial Write and Read Example at 460800 reading a series of NMEA data.  When I type the baud rate in directly I get garbled output that clearly is decoding since the delimiter is 0xA is being detected.  On Tera Term the data is decoding fine.  I looked through the forum but couldn't find exactly what I'm referring to.

Very occasionally I will see a line get decoded correctly, usually the first line when the vi is run.

Any suggestions?

Regards,

-SS

[crossrulz]

What is the device you are getting this information from?  Could you share all of the Tera Term settings?

It may appear that a 0xA is being read, but that could easily be from random data in the read bits.  It really does look like you have some setting wrong.  Perhaps the number of stop bits, data bits, or parity?

[ShotSimon]

Hi Crossrulz,

Termination is CR and LF so either char will decode in Teraterm

-SS

[crossrulz]

I doubt the UTF setting is an issue.  Everything else looks fine.  The only other time I have seen something like this was when I had a device that just constantly spit out data (no breaks between messages).  It was kind of a luck of the draw for when I connected if the bits were lined up correctly to properly read the messages.  I had to program a seemingly massive number of retries to my initialization code in order for it to lock in properly.  But that also caused issues with Putty (I have very limited experience with TeraTerm).  Are you getting any errors from the LabVIEW code?  I'm specifically thinking framing errors from the VISA Read.

[ShotSimon]

When the vi exits. -SS

[ShotSimon]

I'm wondering if there is an issue with VISA and SiLabs CP2105 USB to UART at this baud rate.

There are some posts on the SiLabs forum but I have not gone through them all.

-SS

[RavensFan]

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@ShotSimon wrote:

I'm wondering if there is an issue with VISA and SiLabs CP2105 USB to UART at this baud rate.

There are some posts on the SiLabs forum but I have not gone through them all.

-SS

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I'd go with that theory.  460800 baud sounds MUCH faster than any typical serial application I've heard of.

[ShotSimon · Accepted solution]

Painfully simple error on my part.  I entered the 460800 into the baud rate field not realizing I was just changing the label.  The value was 9600 baud hence the garbage output.

The fix was to open the TypeDef and either add the higher baud rate or just use a constant.

Thanks for your help, I should have posted the code.

Regards,

-SS