Star Network

Description

This Star Network application uses the SPARK Wireless Core to implement a star network topology. It consists of 3 SPARK devices, one Coordinator and two Nodes. Communication is bidirectional between a Coordinator and a Node. This application provides a basic example of how to configure a point-to-multipoint connection.

Behavior

The Coordinator communicates bidirectionally with each Node. The Nodes do not communicate with each other. There are two types of information exchanges in this application.

  1. Count Values: The Nodes send a “count value” to the Coordinator and the Coordinator sends a “count value” to both Nodes. Each device displays the count value it receives on a display linked to its serial interface. To see the messages, the user must connect a terminal emulator software to the device’s serial port on its PC.

  2. Switch State: The transmitted payload also contains device’s switch state. The receiving device uses a LED to represent the transmitting device switch state.

Application Schedule

The following diagram illustrates the general structure of the schedule used in this application.

Star Network schedule

Figure 25: Star Network application’s schedule.

Coordinator Device

On the Coordinator, LED0 or LED1 would turn on if SW1 on Node 1 or Node 2 is pressed respectively. Pressing SW1 or SW2 on the Coordinator will turn on LED1 on Node 1 or Node 2 respectively.

Interface

Name

Description

SW1

Node 1 Switch State

Send SW1 state to Node 1 and turn on its LED1.

SW2

Node 2 Switch State

Send SW2 state to Node 2 and turn on its LED1.

LED0

Node 1 Switch Press

Turn on LED when SW1 on Node 1 is pressed.

LED1

Node 2 Switch Press

Turn on LED when SW1 on Node 2 is pressed.

LED2

N/A

N/A

Node 1 Device

Pressing SW1 on Node 1 turns on LED0 on the Coordinator. LED1 turns on if SW1 is pressed on the Coordinator.

Interface

Name

Description

SW1

Switch state

Send SW1 state to Coordinator and turn on its LED0.

SW2

N/A

N/A

LED0

N/A

N/A

LED1

Switch Press

Turn on LED1 when SW1 on Coordinator is pressed.

LED2

N/A

N/A

Node 2 Device

Pressing SW1 on Node 2 turns on LED1 on the Coordinator. LED1 turns on if SW2 is pressed on the Coordinator.

Interface

Name

Description

SW1

Switch state

Send SW1 state to Coordinator and turn on its LED1.

SW2

N/A

N/A

LED0

N/A

N/A

LED1

Switch Press

Turn on LED1 when SW2 on Coordinator is pressed.

LED2

N/A

N/A

Configuration

Build

Setting a compile option is required on the Node devices since more than one can be used. The following table shows the possible value associated with each Node. Note that this is done automatically with the provided build configurations in the STM32CubeIDE project.

Role

Value

Node 1

NODE1

Node 2

NODE2

Terminal

Host terminal configuration should be as follows:

  • Speed (baud): 115200

  • Data bits: 8

  • Stop bit: 1

  • Parity: None

  • Flow control: None