Editing Programmable logic device (section)

== CPLDs ==
{{main|Complex programmable logic device}}

PALs and GALs are available only in small sizes, equivalent to a few hundred logic gates. For bigger logic circuits, complex PLDs or [[CPLD]]s can be used. These contain the equivalent of several PALs linked by programmable interconnections, all in one [[integrated circuit]]. CPLDs can replace thousands, or even hundreds of thousands, of logic gates.

Some CPLDs are programmed using a PAL programmer, but this method becomes inconvenient for devices with hundreds of pins. A second method of programming is to solder the device to its printed circuit board, then feed it with a serial data stream from a personal computer. The CPLD contains a circuit that decodes the data stream and configures the CPLD to perform its specified logic function. Some manufacturers, such as [[Altera]] and [[Atmel|Atmel (now Microchip)]], use [[JTAG]] to program CPLDs in-circuit from [[Standard Test and Programming Language|.JAM]] files.