Editing Programmable logic device (section)

== Other variants ==
These are microprocessor circuits that contain some [[Fixed-function|fixed functions]] and other functions that can be altered by code running on the processor. Designing self-altering systems requires that engineers learn new methods and that new software tools be developed.

PLDs are being sold now that contain a microprocessor with a fixed function (the so-called ''core'') surrounded by programmable logic. These devices let designers concentrate on adding new features to designs without having to worry about making the microprocessor work. Also, the fixed-function microprocessor takes less space on the chip than a part of the programmable gate array implementing the same processor, leaving more space for the programmable gate array to contain the designer's specialized circuits.