microReticulumTbeam/exercises/05_SD_Card_Watcher/README.md

Exercise 05: SD Card Watcher

This exercise continuously watches SD card presence and prints state-change events.

Watcher behavior:

1. Initializes PMU and enables SD power rail (AXP2101 BLDO1).
2. Polls for card changes with debounced state transitions.
3. Emits events only on change:
   • EVENT: card inserted/mounted
   • EVENT: card removed/unavailable
   • EVENT: no card detected
4. On mount event, prints card info and runs SD write workflow.
5. Every 15 seconds while mounted, runs a periodic write/permission check.
6. Uses fast preferred probe (HSPI @ 400k) and occasional full fallback scan.

Files used in this exercise:

• /Exercise_05_test.txt
• /test/testsub1/testsubsub1/Exercise_05_test.txt

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