Lattice Semiconductor ISPLSI1016-80LJ: A Comprehensive Technical Overview of the High-Density Programmable Logic Device

The Lattice Semiconductor ISPLSI1016-80LJ represents a pivotal component in the history of high-density Programmable Logic Devices (PLDs). As a member of the pioneering ispLSI 1000 family, this device combined significant logic integration with the revolutionary capability of In-System Programmability (ISP), a feature that dramatically altered design and prototyping workflows. This article provides a detailed technical examination of its architecture, features, and applications.

Architecture and Core Features

At its heart, the ISPLSI1016-80LJ is a High-Density PLD built on a Generic Logic Block (GLB) architecture. The device is comprised of 16 GLBs, each containing programmable AND/OR arrays and configurable registers. These blocks are interconnected by a global, high-speed Programmable Interconnect Array (PIA), which routes signals between any GLB and any I/O pin efficiently, ensuring predictable timing performance.

The device boasts a total of 1,000 usable gates and offers 64 I/O pins, along with 4 dedicated input pins. A key specification is its -80LJ speed grade, indicating a maximum pin-to-pin delay of 7.5ns and a system frequency (fmax) of up to 80 MHz, making it suitable for a wide range of moderate-speed applications.

The most defining characteristic of this device is its In-System Programmability (ISP). Utilizing a simple 5-wire interface (SDI, SDO, SCLK, MODE, ispEN), the device could be reprogrammed while soldered onto a printed circuit board (PCB). This eliminated the need for physical handling and dedicated programming sockets, reducing costs and accelerating development cycles.

Key Advantages and Design Benefits

Integration: By consolidating numerous TTL logic chips and smaller PLDs into a single package, the ISPLSI1016 enabled more compact, reliable, and power-efficient PCB designs.

Design Flexibility: The reprogrammable nature of the device allowed for rapid design iterations and easy last-minute changes or field upgrades, a significant advantage over fixed-function ASICs.

Reduced Time-to-Market: ISP streamlined the prototyping and debugging process, allowing engineers to validate and modify designs in the target hardware environment quickly.

Typical Applications

The versatility of the ISPLSI1016-80LJ made it a popular choice for glue logic integration and control functions in various systems, including:

Data Communication and Networking: Used for address decoding, state machine control, and bus interfacing in routers, hubs, and network cards.

Computer Peripherals: Integrating control logic in hard disk drives, printers, and scanners.

Industrial Control Systems: Implementing timing, sequencing, and interface logic in automated equipment.

Military and Aerospace: Its suitability for low-volume, high-reliability applications made it a candidate for these demanding fields.

Conclusion and Legacy

The Lattice Semiconductor ISPLSI1016-80LJ stands as a testament to a critical evolutionary step in digital logic design. It successfully bridged the gap between simple PLDs and more complex FPGAs, offering a robust blend of density, speed, and unparalleled reprogrammability. While later surpassed by advanced FPGAs and CPLDs with greater capacity and features, its ISP technology set a new standard for design flexibility. For engineers today, understanding such devices provides valuable historical context for the development of modern programmable logic.

ICGOODFIND: The Lattice ISPLSI1016-80LJ was a groundbreaking high-density CPLD that popularized In-System Programmability (ISP), enabling faster development and more integrated designs. It excelled at consolidating glue logic with its 1,000-gate capacity and 80MHz performance, making it a cornerstone of 1990s digital design.

Keywords: In-System Programmability (ISP), High-Density PLD, Programmable Interconnect Array (PIA), Generic Logic Block (GLB), CPLD Architecture