Minimum functional blocks for an HDL stepper-motor design A robust HDL stepper-motor controller must, at minimum, include which pair of functional blocks to translate step commands into coil drive patterns?

Introduction / Context:
Stepper-motor control is about mapping a desired step index (position increment) into a known pattern of coil energization. In HDL, this is usually split into two core parts: counting and decoding.

Given Data / Assumptions:

• An up/down counter represents the current step position.
• A decoder/sequencer maps that count to coil drive patterns (full-step, half-step, etc.).
• Additional blocks (timers, PWM for current control) may be added, but are not strictly minimal.

Concept / Approach:
The counter keeps track of where you are in the sequence. The decoder (often implemented as a case statement) translates the numerical count into phase lines to energize the motor coils. Without both, you cannot produce a deterministic, repeatable stepping sequence.

Step-by-Step Solution:

Verification / Alternative check:
Simulate a sequence of steps and record the output bits; compare to a reference table for your stepping mode. In hardware, check with a logic analyzer or LEDs on phase lines.

Why Other Options Are Wrong:

• Variables/processes; types/bits: These are HDL constructs, not functional blocks.
• Sequencers and multiplexers: A “sequencer” is often synonymous with the decoder here, but without the counter there is no step index; the canonical minimal pair is counters and decoders.

Common Pitfalls:
Forgetting to wrap the counter correctly (modulus), or mismatching count order with the physical motor wiring, causing jitter or reverse rotation.

Final Answer:
Counters and decoders