XRP Power States and Safe Oscilloscope Measurement

System Power Architecture and USB Isolation

The XRP platform utilizes a dual-power architecture. Because the system draws power from two independent sources, the physical battery switch does not act as a universal power disconnect:

The physical battery switch exclusively isolates power from the AA battery pack.
Connecting a USB-C cable energizes the 5V and regulated 3.3V logic rails independently.
The microprocessor and expansion headers remain fully active when connected via USB, regardless of the battery switch position.

Defined Operational States

Standardizing physical interactions with the hardware into two defined states helps maintain signal integrity and prevent unintended actuator engagement.

Operational State	Pre-conditions	Authorized Actions	Rationale
Zero-Power State	USB-C completely disconnected; physical battery switch set to OFF.	Inserting, removing, or modifying jumper wires, sensors, or probe tips. Modifying Red Pitaya input-range jumpers.	Ensures complete electrical isolation before altering the physical circuit topology.
Safe Testing State	USB-C connected (logic powered); physical battery switch set to OFF.	Executing code; probing logic signals on the oscilloscope.	Powers the RP2350 logic for Red Pitaya measurement while preventing high-current motors from engaging.

Red Pitaya Measurement Constraints

The following configurations ensure the Red Pitaya operates safely within its input thresholds and maintains measurement accuracy:

10x Attenuation Requirement: The Red Pitaya's LV input range is specified at approximately ±1V at the board input.
Probe Configuration: To measure 3.3V logic signals safely, both the physical switch on the probes and the Red Pitaya software attenuation are set to 10x.
Hardware Range: The physical hardware jumpers on the Red Pitaya are kept in the LV (±1V) position.
Reference Grounding: Probe ground clips connect exclusively to a designated XRP Ground (GND) pin.
Short Circuit Prevention: Connecting a ground clip to a signal pin or a 3.3V power supply rail creates a direct short circuit.

Standardized Shutdown Procedure

A systematic shutdown procedure minimizes the risk of transient voltage spikes and establishes a consistent laboratory routine.

Halt the MicroPython execution within the XRPCode IDE.
Verify via the oscilloscope interface that all electrical waveforms have ceased repeating.
Disconnect the USB-C cable from the XRP Controller.
Confirm the physical battery switch is in the OFF position.
Proceed with altering, changing, or removing system wiring only after the preceding steps are complete.