## Buttons
There are three buttons
![T-Beam SUPREME](../img/20260212_182225_Thu.png)

![](../img/20260212_182300_Thu.png)

From Antenna to USB port:
1) RESET
2) POWER
3) BOOT
  ![](../img/20260212_184521_Thu.png) 

## RESET
The RESET button only needs to be depressed for less than 1 second.  Doing so will cause the unit to reboot.  If you have a "screen" monitor on the USB device, it will be disconnected.  A good way to capture boot posting messages from within the unit is to have your command in a console ready to execute by depressing the RETURN key and you depress RETURN immediately after you depress the unit's RESET button, possibly allowing 1/2 second to allow kernel to recognize the new USB device, i.e. /dev/ttyACM0
## POWER
If your unit is powered OFF, simply depress the POWER button will start the unit.  If the unit is powered ON, then depressing the POWER button and holding it down for 6 second will cause the unit to power down.  The OLED display will go dark when the unit has successfully been powered down.

## BOOT
A) TODO: what happens when unit is powered ON?
B) TODO: what happens when unit is powered OFF?
C) To upload new binary image: depress the BOOT button and hold down, then while holding down the BOOT button disconnect the USB line and then reconnect the USB line and then lift up on the BOOT button.  This will cause the unit to await an upload of an image to be stored in its FLASH memory.  See further how to flash a new image in the section "Flashing Binary".  Note: although the uploader may state it is trying to reset after successful installation of the new image, it seems that software attempt does not work and you have to manually depress the unit's RESET button to force a RESET.  Remember, if you want to see the boot's posting, you should have your terminal ready to run "screen" so you capture the initial postings after you click RESET.
# Exercises
These are progressve tests you can run to confirm how to access the unit's functionality and validate your workbench.

Exercise 00: 00_usb_radio_check

Exercise 01: ASCII ping-pong over LoRa (serial only)

Exercise 02: Add OLED display

Exercise 03: Add SD logging

Exercise 04: Replace ASCII payload with microR packets

Exercise 05: SD provisioning with identity.bin, peer list, beacon

Each exercise is self-contained:

  its own platformio.ini
  its own src/main.cpp
  its own README.md with exact commands

To clean:

	pio run -t clean

Nuclear option:

     rm -rf .pio

Rebuild:

     pio run -e node_a

     pio run -e node_b

## Upload existing firmware (will not recompile if unchanged)
### Upload node A (set your port)
pio run -e node_a -t upload --upload-port /dev/ttyACM0

### Upload node B
pio run -e node_b -t upload --upload-port /dev/ttyACM1

To monitor both:

	screen /dev/ttyACM0 115200
	screen /dev/ttyACM1 115200

Attach antennas (transmitting without antenna will cause power feedback and likely destroy your circuits)
Keep boards at least ~30 cm apart so you don’t desense the receivers.

shared board pin headers in one place: 
  shared/
    boards/
      tbeam-s3-core_pins.h