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/*---------------------------------------------------------------------------*\
FILE........: dac_ut.c
AUTHOR......: David Rowe
DATE CREATED: May 31 2013
Plays a 500 Hz sine wave sampled at 16 kHz out of PA5 on a Discovery board,
or the speaker output of the SM1000.
\*---------------------------------------------------------------------------*/
/*
Copyright (C) 2013 David Rowe
All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License version 2.1, as
published by the Free Software Foundation. This program is
distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <assert.h>
#include "stm32f4_dac.h"
#define SINE_SAMPLES 32
/* 32 sample sine wave which at Fs=16kHz will be 500Hz. Note samples
are 16 bit 2's complement, the DAC driver convertsto 12 bit
unsigned. */
short aSine[] = {
-16, 6384, 12528, 18192, 23200, 27232, 30256, 32128,
32752, 32128, 30256, 27232, 23152, 18192, 12528, 6384,
-16, -6416, -12560, -18224, -23184, -27264, -30288, -32160,
-32768, -32160, -30288, -27264, -23184, -18224, -12560, -6416
};
int main(void) {
dac_open(DAC_FS_16KHZ, 4*DAC_BUF_SZ, 0, 0);
while (1) {
/* keep DAC FIFOs topped up */
dac1_write((short*)aSine, SINE_SAMPLES, 0);
dac2_write((short*)aSine, SINE_SAMPLES, 0);
}
}
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