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Topic: SOLVED - Serial1.begin(57600) = 57.600 kHz ? (Read 944 times) previous topic - next topic

ted


ted


Southpark

#47
May 18, 2018, 03:27 pm Last Edit: May 18, 2018, 03:33 pm by Southpark
On the drawing frequency is not changing but presence of the pulse, 0/1
"Re: Serial1.begin(57600)"

If we go back to your original post (the title of this thread), then ..... the 57600 refers to serial communications signalling rate. And, to understand serial communications signalling rate, it's necessary to learn about serial communications.

As for your question about whether or not '57600' can be linked (somehow) to a measurable frequency........ then, yes..... it could be linked to 57.6 kHz ........ that's if you assume that the serial communications signalling rate is maintained (sustained).

And..... USB serial communications (itself) does not involve PSK.

airzone

If you are connecting a scope to a USB camera, you're not talking about that...


However if you are trying to read TTL serial communications on a scope, try https://electronics.stackexchange.com/questions/17562/how-to-read-serial-data-from-oscilloscope for a bit of guidance. You should be able to write up a program to loop writing a specific character to the serial port so that you can catch it for analysis. But only after you put the USB camera in a different room to the scope. lol


ted

As I said in post # 22 - the results


ted


MrMark

#51
May 18, 2018, 04:28 pm Last Edit: May 18, 2018, 04:29 pm by MrMark

That's NRZI signaling (link in post #35) with a signalling period of 83.3 nanoseconds (post #21) from a USB full speed (12 MHz signalling rate) bus.

The confusion rises (at least) from not being clear about the distinction between signalling on the TTL serial bus (at the baud rate specified in Serial.begin()) and the signalling on the USB bus.  They are not the same physical bus and do not run at the same rate.  For a USB to serial converter the USB side runs at 12 MHz regardless of the TTL serial rate.

ted

I don't see on oscilloscope 12 MHz on RX or Tx

MarkT

I don't see on oscilloscope 12 MHz on RX or Tx
No indeed - you should see 12Mbaud, however.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

ted


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