1 files changed, 57 insertions, 0 deletions
diff --git a/stm32/src/dac_ut.c b/stm32/src/dac_ut.c
new file mode 100644
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+++ b/stm32/src/dac_ut.c
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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);
+    }
+
+}