Hardware Design And Implementation Of Digital Circuit Board Testing System

With the development of digital electronics technology, testing has been the most expensive,difficult and time-consuming part in digital circuit design. How to test the digital circuit boardeffectively has close relationship with the development time and reliability issues of digital systems.According to the defects of testing on manual such as complicated process, workload and lowreliability by using an oscilloscope, multimeter, logic analyzer and other equipments, a generalhigh-performance and automated digital circuit board testing system is researched in this paper. Itskey performance indicators are: Testing frequency can reach50MHz and is adjustable; Testing level iscompatible to-6V~+9V and can be programmed in steps of100mV; Total256testing channels canwork synchronously; Each channel’s memory depth is up to1MBits, current drive capability is50mAwith overload protection and can work as input or output both for three-state.The main content introduced in this paper is the hardware implementation and driver design ofthe digital circuit board testing system. The core processing system is designed by FPGA+SDRAM tosolve the defects such as low flexibility, small memory depth, slow testing speed and other issues intraditional systems. The testing vectors sending module can output three-state which is more diversethan traditional systems, and the testing vectors receiving module use two comparator structure, todetect high, low and uncertain level, to improve fault judgment accuracy. The process of testing isdescribed as follow: The computer firstly initiates testing level, testing frequency and testing channelsand transmit the testing vectors to the target board, and then testing vectors is sent by sending moduleinto the digital circuit board under test. Finally the receiving module aquire the responsed vectors bythe board under test and upload it to the computer. Operators can detect and analysis the digital circuitboard under test by comparing the testing vectors and the responsed vectors.After field debugging and verification, the digital circuit board testing system discussed in thispaper can achieve the desired performance and parameters steadily.