microReticulumTbeam/exercises/04_SD_card/README.md

Exercise 04: SD Card

This exercise loops forever. Each cycle:

1. Prints Sleeping 10 seconds and waits 10 seconds.
2. Detects and mounts the SD card.
3. Prints card and filesystem info (type/size/used).
4. Writes /Exercise_04_test.txt with:
   • This is a test
5. Ensures nested directories exist:
   • /test/testsub1/testsubsub1
6. Writes nested file:
   • /test/testsub1/testsubsub1/Exercise_04_test.txt
7. If either target file already exists, prints warning, erases it, then recreates it.
8. Demonstrates permission behavior:
   • Notes FAT does not provide Unix chmod/chown.
   • Shows access behavior via FILE_READ vs FILE_WRITE modes.

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