please help with serial communication

[Coq_Rouge]

I am fully aware about the fact that you use a PIC MCU in this task. But my code shows all the steps. If you want to know how setup serial communication in Labview. Go to help in the toolbar. Select Find examples and do a search for serial. The Example finder is a very useful tool then you are stuck. Also set the Context help on in the same menu. Do this every time you start Labview

[sfhj]

just i want to make simple modulation on this program to plot the same sine wave signal that i send it via usart

[sfhj]

i need some help as iam not professional

Message Edited by sfhj on 05-30-2010 09:52 AM

[Coq_Rouge]

What samplerate do you use?

[sfhj]

520833 bps

[Dennis_Knutson]

The waveform that you digitize needs to be a fraction of the rate that you are transmitting. Try something around 1000 Hz and modify the example. It's just silly to be doing a write and you need to place a while loop around the read. NEVER use the run continuous button.

[sfhj]

is not basic read write serial that in the example work well when  modulate  it ?

[Dennis_Knutson]

The example is just a starting point. Have you taken the tutorials? The constant configuring of the serial port is just a waste of time that you do not have and the relationship of the input waveform and the serial transmission has nothing to do with LabVIEW. It has everything to do with sampling theory. Are you familiar with Nyquist? At 9600 baud, you would be able to send a 4800 Hz signal and determine the frequency. It would NOT look anything like a sine wave.

[sfhj]

i know nyquist  and his theory fs>=2 fmax

but what is the use of it in the program why didnot you tell me how to make the program and then i will modulate it

thanks

[Coq_Rouge]

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Dennis Knutson wrote:
The example is just a starting point. Have you taken the tutorials? The constant configuring of the serial port is just a waste of time that you do not have and the relationship of the input waveform and the serial transmission has nothing to do with LabVIEW. It has everything to do with sampling theory. Are you familiar with Nyquist? At 9600 baud, you would be able to send a 4800 Hz signal and determine the frequency. It would NOT look anything like a sine wave.

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Just a comment on Samplerate. I have noticed from the Basic code that Sfhj convert the 10 bit ADC result to a string before sending it out on the RS232 link. So each transmission will contain up to 4 bytes. To transmit a byte you at least need 1 start and stop bit, 10 bit is needed to transfer a byte. So at 9600 bit pr second the max theoretical samplerate will be 9600/(4*10) or 240 samples pr second. Even if you use a binary protocol and only use 2 bytes to transfer the samples the max samplerate will be 440 samples pr second limited by the 9600 bit rate.