sound_task.h File Reference

Header file for the sound task system. More...

#include <stdint.h>
#include "stm32f4xx_hal.h"

Go to the source code of this file.

Data Structures
struct	SoundTask
	Structure that represents the sound task state and configuration. More...

Macros
#define	SAMPLE_RATE   44100U
#define	PWM_FREQ   88200U
#define	STEP_RATIO   (PWM_FREQ / SAMPLE_RATE)

Typedefs
typedef void(*	sound_fcn_t) (SoundTask *sound_task)
	Function pointer type for sound state functions.

Functions
void	sound_task_run (SoundTask *sound_task)
	Executes the current sound task state.
void	sound_task_state_0_init (SoundTask *sound_task)
	Initializes the sound task (state 0).
void	sound_task_state_1_wait (SoundTask *sound_task)
	Waits for sound flags (state 1).
void	sound_task_state_2_laser (SoundTask *sound_task)
	Starts the interrupts and sets the array pointer for the laser sound(state 2).
void	sound_task_state_3_hit (SoundTask *sound_task)
	Starts the interrupts and sets the array pointer for the hit sound(state 3).
void	sound_task_state_4_win (SoundTask *sound_task)
	Starts the interrupts and sets the array pointer for the win sound(state 4).
void	sound_task_state_5_start (SoundTask *sound_task)
	Starts the interrupts and sets the array pointer for the start sound(state 5).
void	sound_task_state_6_stop (SoundTask *sound_task)
	Stops the interrupts and PWM for speaker after sound played (state 6)

Variables
const int16_t *	audio_buf_ptr
volatile uint32_t	audio_buf_len
volatile uint32_t	sample_index
volatile uint8_t	pwm_div_count
volatile uint32_t	playing

Detailed Description

Header file for the sound task system.

Author

Andrew Carr

Created on: May 22, 2025

Macro Definition Documentation

PWM_FREQ

#define PWM_FREQ   88200U

Output Timer PWM frequency

SAMPLE_RATE

#define SAMPLE_RATE   44100U

Audio sample rate

STEP_RATIO

#define STEP_RATIO   (PWM_FREQ / SAMPLE_RATE)

Step ratio for

Typedef Documentation

sound_fcn_t

typedef void(* sound_fcn_t) (SoundTask *sound_task)

Function pointer type for sound state functions.

Each state function must take a pointer to SoundTask as its argument.

Function Documentation

sound_task_run()

void sound_task_run

(

SoundTask *

sound_task

)

Executes the current sound task state.

Parameters

sound_task

Pointer to the SoundTask instance.

Executes the current sound task state.

Checks whether the current state index is valid. If so, it calls the corresponding state function from the task's function pointer array.

Parameters

sound_task

Pointer to the SoundTask instance.

sound_task_state_0_init()

void sound_task_state_0_init

(

SoundTask *

sound_task

)

Initializes the sound task (state 0).

Goes to state 1, waiting for sound flags.

Parameters

sound_task

Pointer to the SoundTask instance.

sound_task_state_1_wait()

void sound_task_state_1_wait

(

SoundTask *

sound_task

)

Waits for sound flags (state 1).

Waits for flags to go high and then sends the state machine into the corresponding state.

Parameters

sound_task

Pointer to the SoundTask instance.

sound_task_state_2_laser()

void sound_task_state_2_laser

(

SoundTask *

sound_task

)

Starts the interrupts and sets the array pointer for the laser sound(state 2).

Assigns the corresponding audio buffer and length to the extern variables. Then, restarts interrupts and PWM for the speaker.

Parameters

sound_task

Pointer to the SoundTask instance.

sound_task_state_3_hit()

void sound_task_state_3_hit

(

SoundTask *

sound_task

)

Starts the interrupts and sets the array pointer for the hit sound(state 3).

Assigns the corresponding audio buffer and length to the extern variables. Then, restarts interrupts and PWM for the speaker.

Parameters

sound_task

Pointer to the SoundTask instance.

sound_task_state_4_win()

void sound_task_state_4_win

(

SoundTask *

sound_task

)

Starts the interrupts and sets the array pointer for the win sound(state 4).

Assigns the corresponding audio buffer and length to the extern variables. Then, restarts interrupts and PWM for the speaker.

Parameters

sound_task

Pointer to the SoundTask instance.

sound_task_state_5_start()

void sound_task_state_5_start

(

SoundTask *

sound_task

)

Starts the interrupts and sets the array pointer for the start sound(state 5).

Assigns the corresponding audio buffer and length to the extern variables. Then, restarts interrupts and PWM for the speaker.

Parameters

sound_task

Pointer to the SoundTask instance.

sound_task_state_6_stop()

void sound_task_state_6_stop

(

SoundTask *

sound_task

)

Stops the interrupts and PWM for speaker after sound played (state 6)

Stops interrupts and PWM for speaker then goes back to the waiting state.

Parameters

sound_task

Pointer to the SoundTask instance.

Variable Documentation

audio_buf_len

volatile uint32_t audio_buf_len

extern

Length current sound buffer

audio_buf_ptr

const int16_t* audio_buf_ptr

extern

Pointer to current sound buffer

playing

volatile uint32_t playing

extern

Flag for when a sound is playing

pwm_div_count

volatile uint8_t pwm_div_count

extern

counter for stepping through audio buf

sample_index

volatile uint32_t sample_index

extern

Index of step in sound buffer