src/wakeword

This folder contains the wake word recognition functionality for the Low Power FFD application.

Table 35 Low Power FFD wakeword

Filename/Directory	Description
wakeword.c	The wake word engine source file. Responsible for the transfer of audio samples into the ASR and handling of wake word detection events.
wakeword.h	The wake word engine header file.

Major Components

The wakeword module provides the application with two API functions:

Listing 32 Wake Word API (wakeword.h)

void wakeword_init(void);
wakeword_result_t wakeword_handler(asr_sample_t *buf, size_t num_frames);

wakeword_init

This function performs the required initialization for the wakeword_handler() function to operate. This involves initializing an instance of devmem_manager_t for use by the ASR abstraction layer and initialization of the ASR unit itself. It is to be called once during startup before any call to wakeword_handler() occurs.

wakeword_handler

This function performs wake word detection logic and reports back to the caller a result, indicating whether a wake word was recognized. Note: this routine is called by audio_pipeline_output(), meaning this routine’s logic should be kept to a minimum to ensure timing requirements are met.

In this implementation a single wake word ID of 1 is defined. Minimal adaptation is needed to support other models supporting other IDs or more than one valid wake word.