dac: update unit-test docs and examples for driver-NG

examples/peripherals/dac/dac_audio/tools/generate_audio_file.py

@@ -0,0 +1,48 @@
+# SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: Unlicense OR CC0-1.0
+import os
+import struct
+import wave
+
+try:
+    from typing import List
+except ImportError:
+    pass
+
+
+def get_wave_array_str(filename, target_bits):  # type: (str, int) -> str
+    wave_read = wave.open(filename, 'r')
+    array_str = ''
+    nchannels, sampwidth, framerate, nframes, comptype, compname = wave_read.getparams()
+    sampwidth *= 8
+    for i in range(wave_read.getnframes()):
+        val, = struct.unpack('<H', wave_read.readframes(1))
+        scale_val = (1 << target_bits) - 1
+        cur_lim   = (1 << sampwidth) - 1
+        # scale current data to 8-bit data
+        val       = val * scale_val / cur_lim
+        val       = int(val + ((scale_val + 1) // 2)) & scale_val
+        array_str += '0x%x, ' % (val)
+        if (i + 1) % 16 == 0:
+            array_str += '\n'
+    return array_str
+
+
+def gen_wave_table(wav_file_list, target_file_name, scale_bits=8):  # type: (List[str], str, int) -> None
+    with open(target_file_name, 'w') as audio_table:
+        print('#include <stdio.h>', file=audio_table)
+        print('const unsigned char audio_table[] = {', file=audio_table)
+        for wav in wav_file_list:
+            print('processing: {}'.format(wav))
+            print(get_wave_array_str(filename=wav, target_bits=scale_bits), file=audio_table)
+        print('};\n', file=audio_table)
+    print('Done...')
+
+
+if __name__ == '__main__':
+    print('Generating audio array...')
+    wav_list = []
+    for wavefile in os.listdir('./'):
+        if wavefile.endswith('.wav'):
+            wav_list.append(wavefile)
+    gen_wave_table(wav_file_list=wav_list, target_file_name='audio_example_file.h')