Application Overview

This application demonstrates Slave SPP Chat between two BT devices.

Click here to download the source code for BT_SPP_Slave Application.

Setup required

  1. Quessence
  2. 32/64-bit PC with minimum 2GB RAM and USB port for power, downloading and debugging software
  3. Windows 7/8/8.1/10 Operating System. It should have the Keil IDE and the CMSIS DAP drivers installed on it. Refer to installation section for download and installation steps.
  4. Smart phone/tablet with Bluetooth spp pro app installed in it. You can download the application from playstore from the following path:


Quessence acts as a BT Slave device with SPP profile running it. Smartphone acts as a BT Master device with SPP app running in it.
Set up Quessence module as a Slave and waits to accept SPP profile level connection from remote device.

After successful SPP connection, Application will wait for data to receive from connected remote device.

If remote device sends data to Quessence, Quessence receives the data and send back the same data to remote device using SPP profile.

Details of the Application

The application (running in Quessence module) includes following steps.

  • Configure Quessence module to act as Slave
  • Accept the connection(SPP) from the Smart phone
  • Loop back the received message

Configuring the Application

Following are the configurable macros in the Application file.

Macro Value Description
Name of the Quessence to appear during scanning by peer devices.
Four byte string required for pairing process.

Open rsi_wlan_config.h file and update/modify following macros:

#define CONCURRENT_MODE                                 RSI_DISABLE

#define RSI_FEATURE_BIT_MAP                             FEAT_SECURITY_OPEN

#define RSI_TCP_IP_BYPASS                               RSI_DISABLE


#define RSI_EXT_CUSTOM_FEATURE_BIT_MAP                  EXT_FEAT_256K_MODE

#define RSI_BAND                                        RSI_BAND_2P4GHZ

Executing the Application

  • Connect Quessence module board to the Windows PC running Keil IDE.
  • Build and flash the application to Quessence .
  • After the program gets executed, Quessence module initializes the SPP profile and waits for the incoming connection.
  • Open Bluetooth SPP pro app on mobile and do the scan until Quessence  module (Ex: "SPP_SLAVE") gets present in the scan list.

  • After the successful scan, select the device and initiate pairing to Quessence module.

  • After initiating paring, Pairing request will pop-up at smartphone side and issue secret key which is given at Quessence module (PIN_CODE ) side.

  • Now initiate connection from the SPP App running in the Smartphone.
  • After successful SPP connection, select "Byte stream mode" to send and receive the data.

  • Send some data (Ex: "redpine signals") from the remote device to Redpine device and same data will send back from Redpine device to remote device. Please refer the given image for sending and receiving data from the remote device.