Design Of Oscilloscope High-speed Protocol Analysis Module

With the continuous development of electronic information technology towards informatization,intelligence,complexity and high speed in modern society,the electrical signals in the electronic system have not only become complex,but also the signal rate has become faster,from 10 Mbps to 1Gbps or even higher.As the mainstream electrical signal test instrument,the traditional digital oscilloscope can not meet the test needs of high-speed serial protocol signal capture,analysis and decoding due to sampling rate and bandwidth limitations.In order to capture and analyze the effective information carried in the high-speed serial protocol signal,based on a high-performance oscilloscope with a sampling rate of 10GSa/s and a bandwidth of 4GHz,this thesis uses field programmable gate array to perform real-time protocol signal capture and analysis on multiple parallel data streams,designs a high-speed serial protocol analysis function module,realizes the protocol analysis and decoding requirements of high-speed serial protocol USB2.0,PCIe1.0 and SATA1.0,and carries out the following research.(1)In the analysis of high-speed serial protocol,according to the signal rate and transmission characteristics of the signals of the above three protocols,the preprocessing unit is designed to preprocess the high-speed serial protocol data by using real-time edge feature search,K-code header recognition,data shift decimation,8b/10 data decoding and parallel data self-descrambling mode to realize the high-speed serial protocol data preprocessing by designing the high-speed parallel data stream after sampling the analog to digital converter.On this basis,the protocol frame is analyzed by the finite state machine and each flag bit and effective information is extracted to realize the real-time analysis of the high-speed protocol.It provides strong support for triggering and decoding the effective data required by the module.(2)In terms of triggering high-speed serial protocol,in order to facilitate users to capture specific protocol signals in real time and quickly,this thesis compares the effective information provided by protocol analysis with the trigger conditions issued by testers in real time,and implements 26 trigger modes,17 types of 18 trigger methods and10 types of 10 trigger modes for USB2.0,PCIe1.0 and SATA1.0 protocols.The above triggered methods are all real-time triggers,which provides great convenience and selectivity for users to capture specific waveform signals.(3)In the decoding of high-speed serial protocols,in order to facilitate users to quickly identify the meaning of the protocol waveform,the protocol decoding tag needs to be displayed synchronously with the waveform.In this thesis,a decoding buffer is designed to encapsulate and cache the decoded data of the high-speed protocol,and upload the decoded data to the software side through the direct memory access reading mode,and the software side parses the valid characters of the decoded packet.Finally,it is drawn in the form of a decoding label below the protocol signal waveform,which realizes the synchronous display of the one-to-one correspondence between the decoding tag and the waveform.This thesis designs and implements the above functions in a high-performance oscilloscope,and after actual machine testing and verification,it realizes the accurate triggering,correct decoding and trigger synchronization display of 480 Mbps USB2.0,2.5Gbps PCIe1.0 and 1.5Gbps SATA1.0 high-speed serial protocols,and verifies the functional correctness,decoding accuracy and label consistency of the high-speed serial protocol analysis module.