@sfhj wrote:
i start anew thread cause i did the program but i cant get the original signal ,i use continuous button is that problem
i use sampling frequency 200 .you comment on small things is that will make difference with you and the original thread they didnot give me specific answer
so would you help please or let that project
It's not that we're not trying to help. All too often new posters will simply create a new thread asking the same exact question when they're not getting the answer they want without making a single mention that they've asked the question and provide a link to the original message. As I noted, indicating the existence of the original thread eliminates duplicate questions and comments from replies. Ravens Fan asked you the same exact questions that were asked in the other thread. This inevitable leads to frustration on your end because you have to repeat yourself and it leads to frustration on our end because we end up feeling like we wasted our time asking something you've already answered, or telling you something you already knew. You have to understand that this is a community made up mostly of volunteers. We are not getting paid to do this. We do this because we try to help people. But ultimately, people who ask for help have a responsibility to the community to play the game fairly as well. Otherwise, everybody loses.
Now that my I've finished my diatribe... You have several problems:
- As indicated, you are using the Run Continuously button in the toolbar. This is wrong. That button is intended for debugging purposes, not for normal operation. You were already told this in the original thread by Denns. Yet I still see no while loop. The program is not going to magically fix itself. YOU have to fix it. Look at the "Advanced Serial Write and Read" example. See the loop?
- You have a race condition due to the local variable. The chart should be inside the case structure and connected to the same wire as the "*(type *) &x" indicator.
- Your conversion of the data you read from the serial port is flawed. You have no way of knowing how many bytes you're getting, but you are always assuming that you're receiving some multiple of 4 bytes since you are trying to convert the string to an array of integers. What if the number of characters is an odd number, like 43? You have to carry around the "left-over" bytes into the next iteration for the next conversion. You cannot guarantee that you will be reading the entire waveform in a single read. How many bytes are being transmitted by the source? The serial port's buffer may not be the same size, and data does not arrive all at once. It comes in as a stream, and you have to read it as a stream.
- I don't understand why you're throwing away data for the chart. You're converting to an array of integers, but for the chart you're only sending the first element. Why? That's guaranteed to make your graph look choppy.
The business about the sampling rate was already covered in the original thread. If you're trying to see the waveform in real-time (in other words see it while it's being generated), then forget it - the serial port does not have the bandwidth or speed required. If you're sampling a waveform at the source and sending a snapshot of it, then that's different.
