PAL Device Fundamentals — Pin/function makeup of a PAL16L8 Considering standard 20-pin PAL16L8 devices, which pin/function mix is correct for inputs and outputs?

Introduction / Context:PAL (Programmable Array Logic) devices offered fixed OR planes with programmable AND arrays and configurable I/O macrocells. The PAL16L8 is a classic part number where “16” relates to the available product-term matrix width and “8” denotes eight outputs (often with active-LOW capability), making it a popular SPLD for glue logic.

Given Data / Assumptions:

• Package: typically 20 pins (VCC and GND consume two pins).
• Eight output macrocells are present (the “8”).
• Remaining user pins are generally available as inputs.

Concept / Approach:Subtract supply pins from the total, then account for eight output macrocells. The standard allocation yields ten input pins and eight output pins, with device-specific options for tri-state control or OE. Therefore, “10 inputs and 8 outputs” matches common PAL16L8 datasheets.

Step-by-Step Solution:Total pins ≈ 20 → minus VCC and GND → 18 user pins.Eight are outputs (macrocell outputs).The remaining user pins serve as inputs (~10 inputs).Hence, PAL16L8 configuration: 10 inputs, 8 outputs.

Verification / Alternative check:Legacy PAL/GAL datasheets list PAL16L8 as having 8 outputs and approximately 10 inputs, corroborating the standard understanding.

Why Other Options Are Wrong:

• 8/8: Understates available inputs.
• 16/16 or 16/8: Do not match the pin budget or the “16L8” part family behavior.

Common Pitfalls:Interpreting “16” as the number of inputs; instead it aligns with internal product-term matrix resources rather than literal user I/O counts.

Final Answer:10 inputs and 8 outputs.