Digi XBee3 802.15.4 User Manual

Serial communication Flow control
Digi XBee3® 802.15.4 RF Module User Guide
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For serial communication to occur, you must configure the UART of both devices (the microcontroller
and the XBee3 802.15.4 RF Module) with compatible settings for the baud rate, parity, start bits, stop
bits, and data bits.
Each data byte consists of a start bit (low), 8 data bits (least significant bit first) and a stop bit (high).
The following diagram illustrates the serial bit pattern of data passing through the device. The
diagram shows UART data packet 0x1F (decimal number 31) as transmitted through the device.
You can configure the UART baud rate, parity, and stop bits settings on the device with the BD, NB,
and SB commands respectively. For more information, see UART interface commands.
Flow control
The XBee3 802.15.4 RF Module maintains buffers to collect serial and RF data that it receives. The
serial receive buffer collects incoming serial characters and holds them until the device can process
them. The serial transmit buffer collects the data it receives via the RF link until it transmits that data
out the serial port. The following figure shows the process of device buffers collecting received serial
data.
Use D6 command and D7 command to set flow control.
Clear-to-send (CTS) flow control
If you enable CTS flow control (D7 command), when the serial receive buffer is more than FT bytes full,
the device de-asserts CTS (sets it high) to signal to the host device to stop sending serial data. The
device reasserts CTS after the serial receive buffer has less than FT bytes in it. See FT command to
configure and read this threshold.

Digi XBee3 802.15.4 Specifications

General

Module Type	XBee3
Protocol	802.15.4
Frequency Band	2.4 GHz
Data Rate	Up to 250 kbps
Range (Line of Sight)	1200 m
Operating Temperature	-40° C to +85° C
Security	AES-128
I/O Interfaces	UART, SPI, I2C
Antenna Options	U.FL
Power Supply	2.1 to 3.6 VDC

Summary

Trademarks and Copyright

Disclaimers

Warranty

Customer Support

Applicable Firmware and Hardware

Firmware Support

Information on supported firmware versions for the module.

Hardware Support

Details on the compatible hardware versions for the module.

Get Started

Verify Kit Contents

Lists the components included in the XBee3 development kit.

Assemble the Hardware

Instructions for assembling and disassembling hardware components.

Configure the Device Using XCTU

Steps for configuring the device using the XBee Configuration and Test Utility.

Perform a Range Test

Procedure for testing RF range and link quality between two modules.

Configure the XBee3 802.15.4 RF Module

Over-the-Air (OTA) Firmware Update

Instructions for updating firmware remotely using XCTU.

Custom Defaults

How to set and manage custom default device configurations.

Modes

Transparent Operating Mode

Device behavior as a serial line replacement for RF transmission.

API Operating Mode

Structured interface for complex communication using packets.

Command Mode

State for interacting with the device via AT commands for configuration.

Serial Communication

Serial Interface

How the module interfaces with host devices via UART or SPI.

Flow Control

Mechanisms to manage data flow and prevent buffer overflow.

SPI Operation

SPI Communications

Details on SPI signals, directions, and functions in slave mode.

Low Power Operation

How sleep modes function with SPI and UART interfaces.

I/O Support

Digital I/O Support

Configuration of digital I/O lines for input, output, and sampling.

Analog I/O Support

Configuration of analog inputs for sampling and PWM outputs.

Periodic I/O Sampling

How to sample I/O pins at a periodic rate.

Digital I/O Change Detection

Triggering samples based on digital pin state changes.

Networking

MAC Mode Configuration

Settings for Digi header and MAC acknowledgments.

Addressing

How source and destination addresses are handled in RF packets.

Encryption

Enabling and controlling AES 128-bit encryption for RF transmissions.

Maximum Payload

Factors affecting the maximum data payload size in packets.

Sleep Support

Sleep Modes

Configurations for Pin Sleep, Cyclic Sleep, and Pin Wake-up modes.

Sleep Parameters

AT commands related to sleep mode configuration and timing.

Sleep Conditions

Factors that prevent the device from entering sleep mode.

AT Commands

Network and Security Commands

Commands for network channel, ID, security, and compatibility settings.

802.15.4 Addressing Commands

Commands for setting source, destination, and network addresses.

UART Interface Commands

Commands for configuring serial communication parameters.

I/O Settings Commands

Commands for configuring the module's digital and analog I/O pins.

I/O Sampling Commands

Commands for reading I/O pin states and generating sample data.

Operate in API Mode

API Mode Overview

Benefits and structure of API mode for device communication.

API Frame Format

Structure and fields of API frames for data exchange.

Frame Descriptions

TX Request: 64-bit Address Frame - 0x00

Frame for sending data to a specific 64-bit address.

AT Command Frame - 0x08

Frame for querying or setting local AT command parameters.

RX Packet: 64-bit Address Frame - 0x80

Frame indicating receipt of data via 64-bit addressing.

AT Command Response Frame - 0x88

Frame indicating the result of an AT Command request.

TX Status Frame - 0x89

Frame indicating the status of a transmitted packet.

OTA Firmware Upgrade Process for 802.15.4

OTA/OTB File

Structure and format of OTA firmware image files.

Create the Image Notify Request

Frame used to inform the client about an available firmware update.

Query Next Image Request

Client request for the next firmware image block.

Image Block Request

Client request for specific bytes of the OTA firmware image.

OTA Error Handling

Troubleshooting common errors during the OTA upgrade process.