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sound: Add sample rate as a parameter for square wave

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At present this value is hard-coded in the function that generates a
square wave. Since sample rates vary between different hardware, it makes
more sense to have this as a parameter.

Update the function and its users.

Signed-off-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Simon Glass 2018-11-15 19:56:13 -07:00
parent 03f11e87a8
commit 7d92b06090
4 changed files with 9 additions and 6 deletions
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2
arch/sandbox/cpu/sdl.c
View File

@ -322,7 +322,7 @@ int sandbox_sdl_sound_start(uint frequency)
if (!sdl.audio_active)
return -1;
sdl.frequency = frequency;
sound_create_square_wave((unsigned short *)sdl.audio_data,
sound_create_square_wave(22050, (unsigned short *)sdl.audio_data,
sdl.audio_size, frequency);
sdl.audio_pos = 0;
SDL_PauseAudio(0);

3
drivers/sound/sound-i2s.c
View File

@ -185,7 +185,8 @@ int sound_play(uint32_t msec, uint32_t frequency)
return -1;
}
sound_create_square_wave((unsigned short *)data,
sound_create_square_wave(g_i2stx_pri.samplingrate,
(unsigned short *)data,
data_size / sizeof(unsigned short),
frequency);

6
drivers/sound/sound.c
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@ -7,11 +7,11 @@
#include <common.h>
#include <sound.h>
void sound_create_square_wave(unsigned short *data, int size, uint32_t freq)
void sound_create_square_wave(uint sample_rate, unsigned short *data, int size,
uint freq)
{
const int sample = 48000;
const unsigned short amplitude = 16000; /* between 1 and 32767 */
const int period = freq ? sample / freq : 0;
const int period = freq ? sample_rate / freq : 0;
const int half = period / 2;
assert(freq);

4
include/sound.h
View File

@ -31,11 +31,13 @@ struct sound_codec_info {
/*
* Generates square wave sound data for 1 second
*
* @param sample_rate Sample rate in Hz
* @param data data buffer pointer
* @param size size of the buffer
* @param freq frequency of the wave
*/
void sound_create_square_wave(unsigned short *data, int size, uint32_t freq);
void sound_create_square_wave(uint sample_rate, unsigned short *data, int size,
uint freq);
/*
* Initialises audio sub system