CPLD

Coolrunner XPLA3 Complex Programmable Logic Devices

At the heart of an XPLA3 device is a Zero Interconnect Array (ZIA). This virtual cross-point switch creates interconnections between two or more function blocks, the exact number being determined by the device type.

The pictorial representation of an XPLA3 in figure1 shows a single function block (yellow area). The function block comprises of a PAL-style AND array and a PLA-style OR array and sixteen macrocells. The arrays are used to create boolean logic functions which are fed into the macrocells and ultimately to the external pins.

Each macrocell provides a register and various multiplexers to determine the signal flow between logic function, associated pin (where applicable) and ZIA as depicted in figure2.