/* | |
* Copyright (C) 2012 Samsung Electronics | |
* R. Chandrasekar <rcsekar@samsung.com> | |
* | |
* SPDX-License-Identifier: GPL-2.0+ | |
*/ | |
#include <common.h> | |
#include <sound.h> | |
void sound_create_square_wave(unsigned short *data, int size, uint32_t freq) | |
{ | |
const int sample = 48000; | |
const unsigned short amplitude = 16000; /* between 1 and 32767 */ | |
const int period = freq ? sample / freq : 0; | |
const int half = period / 2; | |
assert(freq); | |
/* Make sure we don't overflow our buffer */ | |
if (size % 2) | |
size--; | |
while (size) { | |
int i; | |
for (i = 0; size && i < half; i++) { | |
size -= 2; | |
*data++ = amplitude; | |
*data++ = amplitude; | |
} | |
for (i = 0; size && i < period - half; i++) { | |
size -= 2; | |
*data++ = -amplitude; | |
*data++ = -amplitude; | |
} | |
} | |
} |