PicoScope 7 Software
Available on Windows, Mac and Linux
Question regarding Serial Decoding
Question regarding Serial Decoding
Hello,
I am a new user of PicoScope 6 on Windows 10 with a PicoScope 2204.
I have a UART signal from my ARM Microcontroller that i want to visualize/decode using Picoscope.
The UART is configured at 115200/8N1, thus at f=115.2kHz. I can perfectly decode everything using a terminal programm connected to the UART.
When I configure the serial decoding with Picoscope the decoding seems to be dependant on the time window I choose. When I select 200ms/div everything is still decoded properly, but as soon as I "zoom out" and go to like "1s/div" all I get is rubbish. Why is this? Can it be avoided? It seems to be related to the configured sample rate? I am already sampling at 2 GS to be able to decode at 115200 at all.. The further I "zoom out" the higher the sample rate needs to be it seems. But why is this? I assume it should be enough to sample at 2*f, approx: 250kHz do fully capture all the details? Why do I need to increase the sample rate to even more when zooming out? The sample rate should be totally irrelevant for the display option which time should be shown per divison? What am I missing?
See below for some sample screenshots showing my findings. Only at 200ms/div I am able to properly decode the stream as it should be.
I am a new user of PicoScope 6 on Windows 10 with a PicoScope 2204.
I have a UART signal from my ARM Microcontroller that i want to visualize/decode using Picoscope.
The UART is configured at 115200/8N1, thus at f=115.2kHz. I can perfectly decode everything using a terminal programm connected to the UART.
When I configure the serial decoding with Picoscope the decoding seems to be dependant on the time window I choose. When I select 200ms/div everything is still decoded properly, but as soon as I "zoom out" and go to like "1s/div" all I get is rubbish. Why is this? Can it be avoided? It seems to be related to the configured sample rate? I am already sampling at 2 GS to be able to decode at 115200 at all.. The further I "zoom out" the higher the sample rate needs to be it seems. But why is this? I assume it should be enough to sample at 2*f, approx: 250kHz do fully capture all the details? Why do I need to increase the sample rate to even more when zooming out? The sample rate should be totally irrelevant for the display option which time should be shown per divison? What am I missing?
See below for some sample screenshots showing my findings. Only at 200ms/div I am able to properly decode the stream as it should be.
- Attachments
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- 200ms, decode OK
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- 500ms, decode partly still ok
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- 1s, corrupted decode
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- Decode settings
Re: Question regarding Serial Decoding
For a starting point select Views->View Properties and you will have a panel on the right that shows how the scope is set up. The 2GS at the top is the number of samples you would like to collect across the screen, not what you actually get. The panel will show this and should help explain why it will not decode for longer time periods.
Martyn
Technical Support Manager
Technical Support Manager