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/16_PSRAM/README.md

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+# Exercise 16: PSRAM
+
+This exercise demonstrates usage of PSRAM (Pseudo SRAM) on an ESP32-S3 board, alongside regular RAM metrics.
+
+Behavior:
+- Reports heap and PSRAM statistics every second over serial.
+- Shows live heap and PSRAM status on the OLED display (both on same line).
+- Allows you to write/append/read/clear data in a PSRAM-backed buffer (up to ~2MB).
+- Designed as an extension of Exercise 15_RAM to explore larger volatile storage.
+
+Note: the exercise now targets a PSRAM-enabled ESP32-S3 board definition (`freenove_esp32_s3_wroom`). This board profile has 8MB flash + 8MB PSRAM, matching the T-Beam Supreme specifications. If your hardware differs, adjust accordingly.
+
+Sources:
+- LilyGo T-Beam SUPREME datasheet/wiki: https://wiki.lilygo.cc/get_started/en/LoRa_GPS/T-Beam-SUPREME/T-Beam-SUPREME.html
+- PlatformIO board definition: https://docs.platformio.org/page/boards/espressif32/freenove_esp32_s3_wroom.html
+- Local PlatformIO board metadata: ~/.platformio/platforms/espressif32/boards/freenove_esp32_s3_wroom.json
+
+Build and upload:
+
+```bash
+cd /usr/local/src/microreticulum/microReticulumTbeam/exercises/16_PSRAM
+pio run -e amy -t upload
+pio device monitor -b 115200
+```
+
+Commands:
+- `help` - show command menu
+- `stat` - show PSRAM buffer state
+- `read` - read PSRAM buffer contents
+- `clear` - clear PSRAM buffer
+- `write <text>` - write text to PSRAM buffer
+- `append <text>` - append text to PSRAM buffer