1 files changed, 67 insertions, 0 deletions

diff --git a/util/audio_generate_dac_lut.py b/util/audio_generate_dac_lut.py
new file mode 100755
index 000000000..c31ba3d7e
--- /dev/null
+++ b/util/audio_generate_dac_lut.py
@@ -0,0 +1,67 @@
+#!/usr/bin/env python3
+#
+# Copyright 2020 JohSchneider
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# 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 General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+AUDIO_DAC_BUFFER_SIZE=256
+AUDIO_DAC_SAMPLE_MAX=4095
+
+def plot(values):
+    for v in values:
+        print('0'* int(v * 80/AUDIO_DAC_SAMPLE_MAX))
+
+def to_lut(values):
+    for v in values:
+        print(hex(int(v)), end=", ")
+
+
+from math import sin, tau, pi
+
+samples=[]
+
+def sampleSine():
+    for s in range(AUDIO_DAC_BUFFER_SIZE):
+        samples.append((sin((s/AUDIO_DAC_BUFFER_SIZE)*tau - pi/2) + 1 )/2* AUDIO_DAC_SAMPLE_MAX)
+
+def sampleTriangle():
+    for s in range(AUDIO_DAC_BUFFER_SIZE):
+        if s < AUDIO_DAC_BUFFER_SIZE/2:
+            samples.append(s/(AUDIO_DAC_BUFFER_SIZE/2) * AUDIO_DAC_SAMPLE_MAX)
+        else:
+            samples.append(AUDIO_DAC_SAMPLE_MAX - (s-AUDIO_DAC_BUFFER_SIZE/2)/(AUDIO_DAC_BUFFER_SIZE/2) * AUDIO_DAC_SAMPLE_MAX)
+
+#compromise between square and triangle wave,
+def sampleTrapezoidal():
+    for i in range(AUDIO_DAC_BUFFER_SIZE):
+        a=3 #slope/inclination
+        if (i < AUDIO_DAC_BUFFER_SIZE/2):
+            s = a * (i * AUDIO_DAC_SAMPLE_MAX/(AUDIO_DAC_BUFFER_SIZE/2)) + (1-a)*AUDIO_DAC_SAMPLE_MAX/2
+        else:
+            i = i - AUDIO_DAC_BUFFER_SIZE/2
+            s = AUDIO_DAC_SAMPLE_MAX - a * (i * AUDIO_DAC_SAMPLE_MAX/(AUDIO_DAC_BUFFER_SIZE/2)) - (1-a)*AUDIO_DAC_SAMPLE_MAX/2
+
+        if s < 0:
+            s=0
+        if s> AUDIO_DAC_SAMPLE_MAX:
+            s=AUDIO_DAC_SAMPLE_MAX
+        samples.append(s)
+
+
+#sampleSine()
+sampleTrapezoidal()
+#print(samples)
+plot(samples)
+to_lut(samples)