Operate in API mode
API mode overview
Digi XBee® 3 802.15.4 RF Module User Guide
185
API mode overview
As an alternative to Transparent operating mode, you can use API operating mode. API mode provides
a structured interface where data is communicated through the serial interface in organized packets
and in a determined order. This enables you to establish complex communication between devices
without having to define your own protocol. The API specifies how commands, command responses
and device status messages are sent and received from the device using the serial interface or the
SPI interface.
We may add new frame types to future versions of the firmware, so we recommend building the ability
to filter out additional API frames with unknown frame types into your software interface.
Use the AP command to set the operation mode
Use
to specify the operation mode:
AP command
setting
Description
AP
= 0
Transparent operating mode, UART serial line replacement with API modes
disabled. This is the default option.
AP
= 1
API operation.
AP
= 2
API operation with escaped characters (only possible on UART).
The API data frame structure differs depending on what mode you choose.
API frame format
An API frame consists of the following:
n
Start delimeter
n
Length
n
Frame data
n
Checksum
API operation (AP parameter = 1)
This is the recommended API mode for most applications. The following table shows the data frame
structure when you enable this mode:
Frame fields
Byte
Description
Start delimiter
1
0x7E
Length
2 - 3
Most Significant Byte, Least Significant Byte
Frame data
4 - number (n)
API-specific structure
Checksum
n + 1
1 byte
