microReticulumTbeam/exercises/06_RTC_check/README.md

Exercise 06: RTC Check (PCF8563)

This exercise validates RTC read/write and power-off persistence on the T-Beam Supreme.

It:

• Initializes PMU + I2C bus used by RTC.
• Reads RTC at startup.
• Prints RTC every 10 seconds.
• Accepts serial commands:
  • show
  • set YYYY-MM-DD HH:MM:SS
  • help

Build

source /home/jlpoole/rnsenv/bin/activate
pio run -e node_a

Upload

source /home/jlpoole/rnsenv/bin/activate
pio run -e node_a -t upload --upload-port /dev/ttyACM0

Monitor

screen /dev/ttyACM0 115200

Suggested Persistence Test

1. Set the RTC:
   • set 2026-02-14 17:30:00
2. Confirm:
   • show
3. Power off the unit for a few minutes.
4. Power on and run:
   • show
5. Compare expected elapsed time vs RTC output.