Group Assignment Week 5

Group Assignment:

Use the test equipment in your lab to observe the operation of an embedded microcontroller.

Lab Equipment Overview

• Oscilloscope
• Power Supply / Power Meter
• Multimeter

Safety First

Electricity is powerful — think of it like a fire hose. Even low voltages can be dangerous if mishandled.

• Up to ~20V is generally considered safe to touch, but always be cautious.
• Typically we work in the 3.3V or 5V range.
• Always confirm your connections before turning on power.

Power Supply

• Primary source of voltage for testing boards.
• Two kinds: Linear (clean, stable) and Switching (common from outlets and computers, usually 5V).
• Noise = how much the voltage varies. A stable supply has minimal noise.
• You can raise/lower the output voltage — but stay within safe limits.
• Voltage as a “variable”: can drive functions on your board (e.g., stepper motor control).

Multimeter

The multimeter is usually the first tool you use when debugging a board.

• Check resistance (continuity test) to see if circuits are connected.
• Check voltage to confirm correct power delivery.
• Identify shorts that may not be visible.
• Resistance mode (horseshoe symbol): touching probes together shows a baseline value.
• Many meters have a continuity sound mode for quick checks.

Oscilloscope

The oscilloscope measures voltage over time and is useful for seeing live signals and noise.

• Used to measure current fluctuations, clock signals, and power stability.
• Yellow = signal line (e.g., clock). Blue/green = ground reference.
• Ground sometimes shows noise — worth investigating.
• Zoom in to detect small oscillations in “stable” signals.
• Single capture: freezes a moment in time for closer analysis.
• Binary signals: the oscilloscope can visualize fluctuations in code execution.
• Typical range: ±2V around a signal clock interval.

Applications in Code

By manipulating voltage and current in code, you can:

• Control stepper motors at specific intervals.
• Test timing and response of microcontrollers (e.g., Raspberry Pi Pico).
• Correlate oscilloscope signals with code execution for debugging.