This program implements the CESLA firmware with deep sleep modes on the earable device.

This firmware is meant to be used with the RSL10-SENSE-DB-GEVK evaluation board to acquire sound signals from the analog microphones and communicate with the CESLA Android mobile application.

This application can enter one of the following states:

• Advertising mode
  Default state after power up. All stream providers are disabled in this mode. Board periodically sends advertising packets (1s interval by default) to allow other devices to connect to it.

  If no device connects in defined timeout period (default 60s) the device will enter sleep mode. Switch to sleep mode is indicated by red LED blinking once.

• Sleep mode
  In this mode all BLE advertising activity is stopped and all sensors are disabled.

  The RSL10 wakes up periodically (default 1.5s) to check if button PB1 is pressed. If button is pressed it will enter Advertising mode signaled by short blink of green LED.

• Connected Mode
  This mode can be entered from Advertising mode when a device connects to the board. BLE connection will be maintained based on parameters set by master device.

  In this mode stream providers can be turned on if master requests sensor related data:

  • LCA - Left channel audio provider will be enabled after a LCA stream request is received.

  • RCA - Right channel audio provider will be enabled after a LCA stream request is received.

  • DMIC - Digital mirophone audio provider will be enabled after a LCA stream request is received.

  When peer device disconnects the board will enter back into advertising mode.

Certain parameters of the application can be configured using an RTE configuration header. This file is located in the include folder of the application and is called RTE_app_config.h. After opening this file using the CMSIS Configuration Wizard editor it will show all available configuration options.

After the program is flashed and running on RSL10-SENSE-GEVK board it will start connectable advertising over BLE. The BLE name is 'CESLA_BLE_Terminal'. The CESLA Android application or test suite can be used to receive the audio samples and show the data.

The program exposes the following audio stream providers in the application:

• Left channel audio stream
• Right channel audio stream
• On-board digital microphone audio stream

Features extraction stream is not yet implemented in firmware.