Hi All, I'm trying to decode the Waveform (from Oscilloscope) back to the strings(abcdef) what I sent to the serial port. 1.Could you help to give me some advice for the attached program? it should not perform efficiently for the decode. how should I modify the program to make it better? I don't know how to use Digital Waveform Graph to get 0 or 1 for each bit, so I go back to the the Y array of waveform again...... 2.Is there any exist VIs or libraries to do protocol decode well? 3.How to know the stop bits only according to the waveform? because the Oscilloscope could detect the stop bit (1 ,1.5 or 2) automatically without addtional setting. if I don't set the stop bit, the decode make have issues in my program.

Hi yeah, First you need to create a Digital Waveform with multiple signals (not just single signal as in your example). Connect this Waveform to the Group Digital Signals Express VI. There you can group your signals into one Digital Bus. Connect the output of this VI to your Digital Waveform Graph. To enable Expand Digital Buses checkbox LabVIEW help requires: "Y Scale»Expand Digital Buses is available only if Advanced»Show Buses With Lines is disabled and the plot legend is in standard view". https://www.ni.com/docs/en-US/bundle/labview/page/lvhowto/digi_wfg_customizing.html