The Study and Implementation of the Algorithm of Identifying the PLD Pin Types through On-board Analysis

The premise of achieving the reverse PLD (Programmable Logic Device) analysis is to identify the pin types by adopting the method of on-board analysis. How to rapidly and accurately identify all pin types is the key problem. Based on theoretical analysis to inherent relationships about data changes among various types of pins, a highly efficient fixed rate algorithm is brought out to identify pin types of all kinds of PLDs. According to whether there is the clock pins, the PLDs are divided into combinational PLDs and sequential PLDs. Both the effective and the correct rate of the fixed rate algorithm are higher than the former because it adopts the correct identifying sequence and considers more details