[参考译文] TAC5212：I2S 模式下的左右差分输入被记录为单声道

Other Parts Discussed in Thread: TAC5212

https://e2e.ti.com/support/audio-group/audio/f/audio-forum/1666252/tac5212-left-and-right-differential-input-in-i2s-mode-get-recorded-as-mono

部件号： TAC5212

如何重现问题

1. 将 Forcusrite 18i20 线路 3 和 4（差分）输出连接到 TAC5212 的模拟 IN 1 和 2  
2. 将 TAC5212 设置为差分输入模式

amixer -c 0 cset iface=MIXER,name='IN1 Source Mux' 'Analog'
amixer -c 0 cset iface=MIXER,name='IN2 Source Mux' 'Analog'
amixer -c 0 cset iface=MIXER,name='ASI_TX_CH1_EN Capture Switch' on
amixer -c 0 cset iface=MIXER,name='ADC1 Config' 'Differential'
amixer -c 0 cset iface=MIXER,name='ADC1 Full-Scale' '4/5-VRMS'
amixer -c 0 cset iface=MIXER,name='ASI_TX_CH2_EN Capture Switch' on
amixer -c 0 cset iface=MIXER,name='ADC2 Config' 'Differential'
amixer -c 0 cset iface=MIXER,name='ADC2 Full-Scale' '4/5-VRMS'

3.观察 I2C 寄存器

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 00 00 01 00 00 15 35 00 00 00 40 10 00 00 04 00    ..?..?5...@?..?.
10: 52 80 00 00 00 00 00 00 40 00 70 00 00 00 20 30    R?......@.p... 0
20: 02 03 04 05 06 07 00 00 00 10 02 03 04 05 06 07    ??????...???????
30: 00 00 00 00 40 00 00 20 00 00 00 00 00 00 00 00    ....@.. ........
40: 00 00 11 54 00 00 00 00 00 00 00 00 2e 0c 00 00    ..?T.........?..
50: 00 00 a1 80 00 00 00 a1 80 00 00 a1 80 00 00 a1    ..??...??..??..?
60: 80 00 00 00 20 20 20 c9 80 c9 80 20 20 20 c9 80    ?...   ????   ??
70: c9 80 18 18 00 00 00 a0 20 00 c8 00 c0 10 36 00    ????...? .?.??6.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

4.用录音录制音频  

arecord test.wav -f S32_LE -r 48000 -c 2

5.将录音 wav 文件复制到台式电脑上。 并在 VLC 媒体播放器上播放。

6、录音是单声道。 两个录制的频道具有相同的音频）

7.断开其中一个模拟输入并重复录音

8.音频仅在其中一个频道录制（另一个是静音）

9、附带的音频文件插头左出/右出/右入 test.wav