3 Accessing RNBD451 Over UART

The most common application for the host MCU to control the RNBD451 module is via ASCII commands. For development and prototyping purposes, using a terminal emulator to send commands and data over UART is recommended. Any terminal emulator, such as TeraTerm (Windows®) or CoolTerm (Mac® OS X®), is used to control and configure the RNBD451 module via UART on the host PC.

With the RNBD451 module connected to a computer and a serial port enumerated for the UART port, run the terminal emulator to open the COM port using the port settings defined in the following table.

Table 3-1. Default UART Settings
UART Setting Default Value
Baud rate115200
Data bits8
ParityNone
Stop bits1
Flow controlDisabled

To enter Command mode, type $$$ into the terminal emulator. When the RNBD451 module enters Command mode, the RNBD451 module sends the string CMD> via the UART to indicate the start of the Command mode session.

When in Command mode, valid ASCII commands are issued to control or configure the RNBD451 module. All commands end with a carriage return <cr>('\r', \x0d). Do not issue any subsequent command until a response is received for the previous command.

For commands, AOK indicates a positive or successful response, whereas, Err indicates an error or negative response. By default, when the RNBD451 module is ready to receive the next command, the command prompt CMD> is sent to UART.

To return to Data mode, type ---<cr>. Also, in the connected and data channel enabled state, the RNBD451 module can enter into Data mode. For this, it is mandatory to have the UART transparent feature enabled. For details on enabling the UART transparent feature, refer to 5.2.1 Default Service Configure (SS,<hex8>).

Note:
  • The module supports Fast Data mode. In this mode, the module does not enter Command mode even if it receives $$$. To enable Fast Data mode, use command SR. For more details, refer to 5.2.15 Set Application Options (SR,<hex16>).

  • The RNBD451 module supports Low Power mode. If the RNBD451 module’s low power is enabled, the host MCU must wake up the RNBD451 module before sending the UART data out. To wake up the module, pull the UART RX indication pin (PB4) to low.