LPC MicrocontrollersのトピックUSB audio distortion on LPC5411X

USB audio distortion on LPC5411X

Kirill_klk — Thu, 20 Jul 2023 06:49:56 GMT

We have a periodic audio distortion with USB Audio device on LPC54114 MCU (OM13090). The issue can be seen in recorded stream and can be listened on speaker. The period is 4-38 min. The distortion time is 2-5 secs. Codec is WM8904. Sample rate is 16kHz.

The board was connected to PC with Ubuntu 20.04. The example project is lpcxpresso54114_rom_dev_audio_bm.

There are only two changes: 1) Uncommented sine in function void i2s_read(void) in i2s_if.c; 2) Changed divider of sine from 28 to 1 in sine_file.c.

Recording of test audio file was made by command: => arecord -f dat -r 16000 test_ref_1.wav.

Re: USB audio distortion on LPC5411X

xiangjun_rong — Thu, 27 Jul 2023 02:31:45 GMT

Hi,

If you do not change anything, do the sound distortion happen or not?

XiangJun rong

回复： USB audio distortion on LPC5411X

Kirill_klk — Mon, 31 Jul 2023 08:41:31 GMT

Hi,

It is very difficult to reproduce the issue on Windows. We found it only 2 times with and without changes in code. On Linux the situation is worse. We found the issue each time when start recording.