FPGA Design and Implementation with the Lattice LC4064ZE-5TN48C CPLD
The Lattice LC4064ZE-5TN48C represents a specific category of programmable logic devices, often referred to as Complex Programmable Logic Devices (CPLDs). While FPGAs (Field-Programmable Gate Arrays) and CPLDs share the common trait of being user-configurable, they differ in architecture and optimal application areas. This article outlines the design and implementation process specifically for this device, highlighting its unique characteristics within the broader context of programmable logic design.
The LC4064ZE-5TN48C is a member of Lattice Semiconductor's high-performance, low-power ispMACH® 4000ZE CPLD family. It features 64 macrocells, offering a deterministic, pin-to-pin timing model that is ideal for critical control logic, glue logic, and bridging functions between other integrated circuits. Its 5ns pin-to-pin propagation delay ensures fast response times for control-oriented tasks. The device is housed in a thin quad flat pack (TQFP) with 48 pins (5TN48C), making it suitable for space-constrained PCB designs. A key advantage of this family is its ultra-low power consumption, operating at 1.8V core voltage, which is crucial for portable and battery-powered applications.
The design flow for this CPLD follows a standard methodology. It begins with design entry, where the digital circuit is defined using a Hardware Description Language (HDL) like VHDL or Verilog, or through schematic capture. This is followed by functional simulation to verify the logic behavior independently of timing constraints.
The next critical phase is synthesis. The HDL code is translated into a netlist of primitive logic gates and functions (optimized for the CPLD's structure) using Electronic Design Automation (EDA) tools. For Lattice devices, the Lattice Diamond or Lattice Radiant software suites are typically used. These tools allow for design synthesis, place-and-route, and timing analysis.
Implementation involves mapping the synthesized netlist onto the actual resources of the LC4064ZE. This process consists of three main steps:
1. Placement: The software assigns the logic functions to specific macrocells within the device.
2. Routing: The interconnections between these macrocells are established using the CPLD's programmable switch matrix and interconnect resources.
3. Timing Analysis: Static Timing Analysis (STA) is performed to ensure all setup, hold, and propagation delay requirements are met. The predictable timing of CPLDs like the LC4064ZE simplifies this verification process.
After a successful place-and-route, a bitstream file (often with a `.jed` extension for CPLDs) is generated. This file contains the configuration data for the device. The final step is programming. The LC4064ZE supports in-system programming (ISP) via its dedicated JTAG (IEEE 1149.1) interface. This allows the device to be programmed soldered directly onto the printed circuit board, streamlining the manufacturing and debugging process.
ICGOODFIND: The Lattice LC4064ZE-5TN48C CPLD is a robust and efficient solution for applications requiring fast, deterministic logic with minimal power draw. Its design and implementation leverage a mature toolchain, making it an excellent choice for replacing discrete logic ICs, implementing state machines, and handling interface protocol bridging where low cost and low power are paramount.
Keywords: CPLD, Lattice ispMACH 4000ZE, Deterministic Timing, Low-Power Design, JTAG Programming
