Product-term borrowing in MAX+PLUS II (Altera CPLDs): Does the compiler automatically allow a macrocell to borrow up to six product terms from each of three adjacent macrocells in the same Logic Array Block (LAB)?

Introduction / Context:Altera (now Intel) MAX-series CPLDs use product-term macrocells grouped into Logic Array Blocks (LABs). The tools support product-term sharing/expansion to realize wider logic equations than a single macrocell can natively implement. However, the exact borrowing limits depend on family architecture and are not universally “six from each of three adjacent macrocells.”

Given Data / Assumptions:

• MAX+PLUS II supports product-term expansion within a LAB.
• Borrowing limits vary by family (for example, MAX 7000/9000).
• The quoted “six from each of three adjacent macrocells” is a very specific claim.

Concept / Approach:While product-term sharing is real, vendor documentation specifies totals and patterns that differ across devices. Some families allow a macrocell to gain a defined number of additional product terms via expanders, but the numbers and topology constraints (which neighbor, how many, how routed) are architecture-specific. The statement’s exact figures do not represent a general rule for MAX+PLUS II across all CPLDs and are therefore unreliable as a blanket assertion.

Step-by-Step Solution:

Verification / Alternative check:Check the specific MAX family datasheet and the Compiler Help. You will find product-term expansion descriptions, but not a universal “6 from each of 3 neighbors” rule.

Why Other Options Are Wrong:

Common Pitfalls:Memorizing a number from one family and generalizing to all; ignoring fitter reports that show actual product-term usage.

Final Answer:Incorrect