programmable logic device (logic) (PLD)
The term Programmable Logic Device (PLD) refers to various logic chips that can be programmed at the customer site or on-site as Field Programmable Logic Devices (FPLD). Programmability of chips refers to the fact that these chips can be easily modified without the use of costly photomasks. In addition, memory-based PLDs can be reprogrammed over and over again, which is attractive for customer product upgrades.
Programmable Logic Devices are ASICs (Application Specific Integrated Circuit), they are pre-assembled with a wide variety of logics - these can be a few but equally a few hundred - which are linked together according to customer-specific requirements. There are PLDs that are programmable once, One Time Programmable( OTP), others that can be programmed repeatedly. The One Time Programmable PLDs are programmed by electronically burning away a fusible link, a type of microscopic miniature fuse. This technique is also known as the fuse technique. The opposite of the fuse technique is the anti-fuse technique, where instead of destroying a logical link, an additional logical link is built. In this case, insulating silicon is transformed into conducting silicon by the influx of charge.
The reprogrammable ones work memory-based. They store their logic design in Erasable PROMs( EPROM), Electrically Erasable PROMs( EEPROM), Flash memories or Static RAMs( SRAM), where each programmable logic point is assigned to a memory location. The state of the logic operation, whether open or closed, is stored in this location. Programmable logic devices include Simple Programmable Logic Devices( SPLD), Complex Programmable Logic Devices( CPLD) and Field Programmable Gate Arrays( FPGA).
Hardware Description Languages ( HDL) are used as programming languages for the source code of the compilers.