Pinout
The ESP32 XBee was designed to conform to the standard set of XBee pins as found on official devices. Because of this there are a number of named pins on the board that might only be relevant on a fully featured XBee programming board, such as the XBee Grove Development Board.
I am currently designing an XBee proxy board that has both a plug and a socket to add the full functionality of the Grove to existing devices (such as SimpleRTK2B) in a much smaller form factor.
Physical pin number.
Enable pin, resets the ESP32 when pulled low. Connected to the RESET button on XBee programming boards. See also Right Jumper.
Boot mode pin, decides whether to boot into firmware download mode or normal mode. Connected to the BOOT button on the ESP32 XBee. See also Left Jumper.
Autoflashing is the ability of the ESP32 XBee to be automatically reset into firmware download mode when requested by a PC. It is a useful feature when developing for the ESP32, as it removes the need to press buttons every time you want to upload new firmware. See also Jumpers.
Power supply pins. The XBee socket must be capable of providing at least 500mA to the ESP32 XBee.
General purpose input/output pins, as numbered by the ESP32.
Pins 18 (GPIO39) and 20 (GPIO36) are input only pins.
Standard XBee I2C pins.
Not currently used in this firmware, but can be configured to any other pins as needed.
Standard XBee main and auxiliary UART pins.
U0TX and U0RX are the main communication ports for the board.
The flow control pins U0DTR/U0RTS/U0CTS are normally disabled and instead connected to the board Jumpers.
Not currently used in this firmware, but can be configured to any other pins as needed.
ESP32 XBee specific RGB status LED, active low. Red = GPIO21, Green = GPIO22, Blue = GPIO23.
Standard XBee status LEDs.
WiFi connection strength indicator, active high. Shines brightest when connection is good.
Device status indicator, active low. Not currently used in this firmware.
Associate indicator, active high. Not currently used in this firmware.
Standard XBee buttons.
XBee reset button found on most XBee programming boards.
Used for pairing XBees to a network. Not currently used in this firmware.
There are two solder jumper connections on the ESP32 XBee, both used for autoflashing.
Neither jumper has any effect on the SimpleRTK2B as it does not have any connections except for power and TX/RX.
To disconnect the jumpers, simply scrape away the connection between the top and bottom with a sharp object, such as a pair of tweezers. To reconnect, apply some solder with a soldering iron to the two exposed pads.
The left jumper connects the DTR pin of the XBee programming board to the BOOT pin of the ESP32.
The right jumper connects the RTS pin of the XBee programming board to the EN pin of the ESP32.