After various memory exercises, then back to GPS to get UBlox working. UBlox is working. TODO: start libraries, downplay SD Card as we can use memory for interim logging

exercises/17_Flash/README.md

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+# Exercise 17_Flash
+
+This exercise demonstrates using Flash storage as a persistent directory-like file system on an ESP32-S3 board.
+
+Behavior:
+- Mounts SPIFFS at boot and reports total / used / free flash space.
+- Ensures a flash directory at `/flash_logs` exists.
+- Creates a new log file when the device boots, based on the current timestamp: `YYYYMMDD_HHMM.log`.
+- Writes a timestamped line into the new log file once per second.
+- Supports console commands to inspect the current file, read it, clear it, append or rewrite it, and list stored files.
+- Files persist across reboots and are stored in flash.
+
+Build and upload:
+
+```bash
+cd /usr/local/src/microreticulum/microReticulumTbeam/exercises/17_Flash
+pio run -e amy -t upload
+pio device monitor -b 115200
+```
+
+Commands:
+- `help` - show command menu
+- `stat` - show flash / current file status
+- `list` - list files under `/flash_logs`
+- `read` - read the current flash file contents
+- `clear` - clear the current flash file contents
+- `write <text>` - overwrite the current flash file with text
+- `append <text>` - append text to the current flash file
+
+Notes:
+- If the current timestamp file name already exists, the exercise will append a numeric suffix to keep the file unique.
+- On each reboot a new file is created so persistent flash logs accumulate.