How to develop an oscilloscope with 4-channel logic analysis

logic analyzer

In digital circuits, when analyzing or testing digital signals, using an oscilloscope will seem a bit inadequate. Under this influence, we decided to develop an oscilloscope with 4-channel logic analysis. It can measure 1 analog signal and 4 digital signals at the same time. The software effect is shown in the figure.

       We developed the logic analysis function based on the existing oscilloscope OSC802, and realized it through the expansion port reserved by OSC802 (OSC802 reserves four data inputs, so we first developed a four-channel logic analyzer). The design hardware principle is shown in the figure.

The logic analyzer is developed and designed based on OSC802, so the logic analysis and the oscilloscope B channel data use the same digital line, and the B channel data and the logic analyzer data will conflict during the transmission process. However, the 74ls245 can select the data format (logic data or B channel data) to avoid data conflicts.

The development results are tested through the signal source: channel A adds a sine signal, and a 4-channel logic analyzer measures the digital signal. Different colors in the software display area correspond to signals of different lines.