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v2.3.0 - Power Supply Monitoring via Vref (2026-01-07)

What Changed?

This release adds the GET_VREF command for power supply health monitoring. The command reads the ESP32 internal reference voltage (Vref) to detect power supply anomalies. This enables remote diagnostics to identify boards experiencing voltage issues.

What's New

Main Feature: GET_VREF Command

What it does: Reads the ESP32 internal Vref (reference voltage) and returns it in millivolts. Vref indicates the stability of the internal power supply. Normal ESP32 boards report Vref around 1100 mV; abnormally low values may indicate failing power supplies.

How to use it: Send the GET_VREF command via serial to get the current Vref value:

GET_VREF

Response example:

{"type":"response","status":"ok","sent_us":26226619,"vref_mv":1121}

Diagnostics:

  • Normal: 1000-1200 mV (healthy power supply)
  • Warning: 900-1000 mV (marginal)
  • Critical: < 900 mV (power supply failing)

Installation

Quick Start

# Get the release
git checkout v2.3.0

# Build v2 firmware
task v2:build

# Upload to ESP32
task v2:upload

# Monitor serial output
task monitor

What's Different from the Last Version?

✅ Added

  • GET_VREF command for reading ESP32 internal reference voltage (Vref)
  • Power supply health monitoring capability for remote diagnostics
  • Vref-based anomaly detection for failing power supplies

🔧 Changed

  • System Information command count increased from 8 to 9
  • Command dispatch table updated to include GET_VREF handler

Is It Safe to Upgrade?

Backward Compatible: Yes

  • GET_VREF is a new read-only command with no impact on existing features
  • All existing commands remain unchanged
  • No breaking changes to command protocol or response format

Tests Passed

  • ✅ Builds without errors (RAM: 31.4%, Flash: 27.8%)
  • ✅ GET_VREF command executes successfully
  • ✅ Response format matches unified device response protocol
  • ✅ Vref values stable across multiple calls (1121 mV on healthy board)
  • ✅ Anomaly detection: Distinguishes healthy (1121 mV) from failing (2 mV) boards

Release Details

  • Date: 2026-01-07
  • Version: v2.3.0
  • Files Changed: 3 (vref.cpp, v2_command_manager.cpp, config.h)
  • New Commands: 1 (GET_VREF)
  • Breaking Changes: None

Next Steps

  • Power supply diagnostics can now be performed remotely via GET_VREF
  • Consider implementing automatic power supply alerts when Vref drops below threshold
  • Future: Add optional Vref field to periodic GET_STATUS response for continuous monitoring