BT Classic Command Mode Selection
This section describes the AT Command Mode or Binary Mode Selection in UART and USB-CDC.
After the bootloader interaction, the module issues "Loading Done" string in ASCII format to the host. After receiving the "Loading Done" string, based on the first command received from the host, the module selects command mode.
The module reads first 4 bytes, if it matches with "AT+R", it configures AT command mode; otherwise, Binary mode is configured. Once mode is configured, it will remain in same mode until next reset or power cycle.
There is an option in bootloader to select AT+mode or binary mode.
NOTE:
"AT+R" is not case sensitive