This paper provides a tutorial survey of architectures of commercially available high-capacity

field-programmable devices (FPDs). We first define the relevant terminology in the field and then

describe the recent evolution of FPDs. The three main categories of FPDs are delineated: Simple

PLDs (SPLDs), Complex PLDs (CPLDs) and Field-Programmable Gate Arrays (FPGAs). We

then give details of the architectures of all of the most important commercially available chips,

and give examples of applications of each type of device.