Stepper motor HDL control modes: In the stepper motor HDL module, which mode causes the design to ignore counter-driven stepping inputs and instead route external control inputs directly to the phase outputs (manual/direct control)?

Introduction / Context:
Many HDL-based stepper controllers support multiple operating modes. Typical modes include manual (direct) control, automatic full-step sequencing, automatic half-step sequencing, and sometimes jog or microstep variants. The manual/direct mode is useful for testing phase outputs or for external supervisory logic to set phases without the internal step counter advancing the sequence.

Given Data / Assumptions:

• The controller has enumerated modes labeled 1–4.
• In one specific mode, the module bypasses counter inputs and feeds control lines directly to outputs.
• We assume a common convention where Mode 1 denotes manual/direct control for lab verification.

Concept / Approach:
During design bring-up, engineers often want to energize phases individually to verify coil wiring, polarity, and current paths. A “direct” or “manual” mode that ignores the internal step counter simplifies this testing. Assigning this to Mode 1 is a conventional choice in educational projects, making it quick to reach and obvious to use.

Step-by-Step Solution:

Verification / Alternative check:
Waveform simulation should show phase outputs tracking the external control pins directly when Mode 1 is active, while in other modes the outputs follow sequencer or counter timing.

Why Other Options Are Wrong:

• Modes 2–4: Commonly mapped to full-step, half-step, or jog/auto-run sequences; they use internal counters.
• Mode 0 (if present): Not listed as a valid choice in the project’s mode table.

Common Pitfalls:
Attempting wiring verification while the sequencer is running; misinterpreting coil order because the counter keeps advancing; forgetting to disable current to avoid overheating when holding a single phase energized.

Final Answer:
1