The Design Of General Protocol Trigger And Decoding Module For Oscilloscope

With the development of modern electronic equipment,various types of data interaction are required within and between equipment,and various communication protocols are born.The coding and transmission methods of these protocol signals are complex and diverse,and testers need other equipment to assist in analyzing protocol signals.As a common signal testing instrument,oscilloscope undertakes the task of protocol analysis.Through the acquisition,analysis and trigger system of oscilloscope,the acquisition,decoding and trigger of protocol signal can be realized.The internal logic of the oscilloscope to decode the same protocol is the same.The protocol decoding function module itself is not necessarily related to the oscilloscope architecture.Oscilloscopes with different architectures are only different on the external control module.Therefore,it is feasible to design a universal oscilloscope protocol trigger and decoding module,and this module can be well transplanted on oscilloscopes with different architectures.At present,the domestic oscilloscope architecture mostly uses FPGA to realize hardware logic,so this paper designs a universal protocol trigger and decoding module based on the oscilloscope that uses FPGA to realize hardware logic.The module is mainly divided into peripheral control module and protocol decoding module.The protocol decoding module is internally divided into protocol analysis module,protocol trigger module and protocol decoding packet generation module.1.Peripheral control module: This module is mainly responsible for enabling control,parameter command interaction,signal data interaction and other functions of each submodule.2.Protocol analysis module: different protocol signals are different in terms of coding mode,framing format and transmission mode.This module extracts the original information carried by protocol signals according to these characteristics of the protocol.3.Protocol trigger module: In order to facilitate the user to capture the interested part of the protocol signal more quickly,a variety of trigger methods are designed according to the protocol transmission characteristics,including status bit trigger,frame type trigger and command event type trigger.4.Decoding packet generation module.In order to visualize the original information carried by the protocol signal,the protocol decoded information is packaged into decoded data packets in a certain format,and the decoded data packets are transmitted to the upper computer.The decoded data packets are sent to the software for analysis and the decoded labels are drawn.The decoded labels and time-domain waveform data are displayed on the oscilloscope screen synchronously.Based on this general architecture,this paper designs and implements the analysis module of MIL-STD-1553 B,ARINC429 and SPMI,and finally performs verification analysis on two digital oscilloscope platforms developed by the teaching and research department.It is verified that the general protocol trigger and decoding module designed in this paper has good portability and can adapt to many different types of oscilloscopes;The above three protocols can be analyzed,and the trigger position is correct and stable;The decoded tag information is correct and synchronized with the time domain waveform data,meeting the requirements of the design index.