src#

This folder contains the core application source.

Table 14 FFD src#
Filename/Directory	Description
gpio_ctrl directory	contains general purpose input handling and LED handling tasks
intent_engine directory	contains intent engine code
intent_handler directory	contains intent handling code
rtos_conf directory	contains default FreeRTOS configuration headers
app_conf_check.h	header to validate app_conf.h
app_conf.h	header to describe app configuration
config.xscope	xscope configuration file
ff_appconf.h	default fatfs configuration header
main.c	main application source file
xcore_device_memory.c	model loading from filesystem source file
xcore_device_memory.h	model loading from filesystem header file

Audio Pipeline#

The audio pipeline module provides the application with three API functions:

Listing 1 Audio Pipeline API (audio_pipeline.h)#

void audio_pipeline_init(
        void *input_app_data,
        void *output_app_data);

void audio_pipeline_input(
        void *input_app_data,
        int32_t **input_audio_frames,
        size_t ch_count,
        size_t frame_count);

int audio_pipeline_output(
        void *output_app_data,
        int32_t **output_audio_frames,
        size_t ch_count,
        size_t frame_count);

audio_pipeline_init#

This function has the role of creating the audio pipeline, with two optional application pointers which are provided to the application in the audio_pipeline_input() and audio_pipeline_output() callbacks.

In FFD, the audio pipeline is initialized with no additional arguments, and instantiates a 3 stage pipeline on tile 1, as described in: Audio Pipeline

audio_pipeline_input#

This function has the role of providing the audio pipeline with the input frames.

In FFD, the input is received from the rtos_mic_array driver.

audio_pipeline_output#

This function has the role of receiving the processed audio pipeline output.

In FFD, the output is sent to the intent engine.

Main#

The major components of main are:

Listing 2 Main components (main.c)#

void startup_task(void *arg)
void vApplicationMinimalIdleHook(void)
void tile_common_init(chanend_t c)
void main_tile0(chanend_t c0, chanend_t c1, chanend_t c2, chanend_t c3)
void main_tile1(chanend_t c0, chanend_t c1, chanend_t c2, chanend_t c3)

startup_task#

This function has the role of launching tasks on each tile. For those familiar with XCORE, it is comparable to the main par loop in an XC main.

vApplicationMinimalIdleHook#

This is a FreeRTOS callback. By calling “waiteu” without events configured, this has the effect of both MIPs and power savings on XCORE.

Listing 3 vApplicationMinimalIdleHook (main.c)#

asm volatile("waiteu");

tile_common_init#

This function is the common tile initialization, which initializes the bsp_config, creates the startup task, and starts the FreeRTOS kernel.

main_tile0#

This function is the application C entry point on tile 0, provided by the SDK.

main_tile1#

This function is the application C entry point on tile 1, provided by the SDK.