Wireless UART Host

This section describes the implemented profiles and services, user interactions, and testing methods for the Wireless UART Host application.

The Wireless UART Host application is a demonstration of the Extended NBU architectural concept, where the Bluetooth LE Host Stack and the Link Layer both run on the NBU core, while the user-facing application runs on the Application core. The communication between the application and the Host is done via the FSCI protocol running on the inter-core RPMSG transport.

The Wireless UART Host application must be flashed together with the NCP FSCI Blackbox application.

Implemented profile and services

The Wireless UART Host application implements both the GATT client and server for the custom Wireless UART profile and services.

  • Wireless UART Service (UUID: 01ff0100-ba5e-f4ee-5ca1-eb1e5e4b1ce0)

  • Battery Service v1.0

  • Device Information Service v1.1

The Wireless UART service is a custom service that implements a custom writable ASCII Char characteristic (UUID: 01ff0101-ba5e-f4ee-5ca1-eb1e5e4b1ce0) that holds the character written by the peer device.

The application behaves at first as a GAP central node. It enters GAP Limited Discovery Procedure and searches for other Wireless UART devices to connect. To change the device role to GAP peripheral, use the ROLESW button. The device enters GAP General Discoverable Mode and waits for a GAP central node to connect.

Parent topic:Wireless UART Host

Supported platforms

The following platforms support the Wireless UART Host application:

  • MCX-W72-EVK

  • FRDM-MCXW72

Parent topic:Wireless UART Host

User interface

Ensure that both NCP FSCI Blackbox (for the NBU core) and Wireless UART Host (for the Application core) have been flashed to the board.

After flashing the board, the device is in idle mode (all LEDs flashing). To start scanning, press the SCANSW button. When in GAP Limited Discovery Procedure of GAP General Discoverable Mode, CONNLED is flashing. When the node connects to a peer device, CONNLED turns solid. To disconnect the node, hold the SCANSW button pressed for 2-3 seconds. The node then re-enters GAP Limited Discovery Procedure.

See the table below for hardware references for the Wireless UART application.

Platform

SCANSW

CONNLED

ROLESW

MCXW72-EVK

SW2

LED2

SW3

FRDM-MCXW72

SW4

Blue LED

SW2

Parent topic:Wireless UART Host

Usage

The application is built to work with another supported platform running either Wireless UART or Wireless UART Host, or with the Wireless UART from the IoT Toolbox application.

When testing with two boards, perform the following steps:

  1. Open a serial port terminal and connect to the two boards, in the same manner described in Testing devices. The start screen is blank after the board is reset.

  2. The application starts as a GAP central. To switch the role to a GAP peripheral, press the role switch. Depending on the role, when pressing the SCANSW, the application starts either scanning or advertising.

  3. As soon as the CONNLED turns solid on both devices, the user can start writing in one of the consoles. The text appears on the other terminal.

  4. After creating a connection, the role (central or peripheral) is displayed on the console. The role switch can be pressed again before creating a new connection. See the figure below.

    Tera Term – received text on Wireless UART

When testing with a single board and the IoT Toolbox, perform the following steps:

  1. Open a serial port terminal and connect the board in the same manner described in Testing devices. The start screen is blank after the board is reset.

  2. Press the role switch button to behave as a GAP peripheral and then press the SCANSW button to start advertising. The IoT Toolbox app can then connect. Select UART instead of Console and start typing, as shown in the Figure.

Parent topic:Wireless UART Host

Parent topic:Bluetooth LE stack and demo applications