DSO Shell only transmits first half of waveform

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wbbnm
Posts: 2
Joined: Sat Aug 11, 2018 7:41 pm

DSO Shell only transmits first half of waveform

Post by wbbnm »

I am trying to transfer waveform data from the DSO Shell to my computer.
I am using a CP210x microUSB convertor board.

The board seems to be working properly and I can transfer some data including settings and measurements.
But when I try to transfer a waveform, I only get the first ~505 samples.
This happens no matter how the data is displayed on the screen.
The last sample I get has all the index, time, and data value information. So I don't think the read is being prematurely truncated.

I have tried changing timeout and buffer sizes in my program.
I am using Microsoft Visual C++ routines CreateFile, SetCommState, SetCommTimeouts, WaitCommEvent, and ReadFile functions.

Do you have any suggestions on what I might be doing wrong?

I have seen indications online that others are able to read the entire 1024 sample data buffer.

Thanks
Bill Boyer
jye1
Posts: 1221
Joined: Wed Feb 20, 2013 4:58 pm

Re: DSO Shell only transmits first half of waveform

Post by jye1 »

It is suggested to use another tool to capture the data and see if it is complete. For example, this is one we frequently use http://www.jyetech.com/Support/teraterm-4.80.exe .
wbbnm
Posts: 2
Joined: Sat Aug 11, 2018 7:41 pm

Re: DSO Shell only transmits first half of waveform

Post by wbbnm »

I had adapted my code from an example I found online. This code read the data byte-by-byte with calls to ReadFile.

I changed the code to read the entire buffer in one call. This works. So I am okay now.

I don't know why the first method didn't work. I could imagine a timing problem with the repeated reads.
But I was getting all the first half of the waveform with nothing missing as far as I could tell.
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