USB distortion LPC5411X

[Kirill_klk]

Dear colleagues,

We have a periodic audio distortion with USB Audio device on LPC54114 MCU. 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.
SW based on lpcxpresso54114_rom_dev_audio_bm from SDK.

Recommendation from TN00031 and https://www.nxp.com/docs/en/errata/ES_LPC5411X.pdf were added in software.

The schematic is similar as OM13090.

Could you plaese help to resolve the issue?

[ZhangJennie]

HI Kirill_klk 

In order to resolve the issue, please let us know how to reproduce the issue with NXP demo board and SDK demo code. We need to reproduce it first.

Thanks,

Jun Zhang

[Kirill_klk]

Please try to play on PC https://www.dropbox.com/s/q4uv9r2ks9bvcnm/test_16khz.wav?dl=0

The board are playing sine from sine_file.c and we uncommented sine in i2s_if.c.

This file was recorded by arecord command on Linux PC. Please see attached pictures.

The issue can be on Audio OUT and can appear after 38-40 mins after start playing.

[ZhangJennie]

HI 

If the problem can be only viewed on custom HW and SW platform, this is for professonal support

https://www.nxp.com/support/support/nxp-engineering-services/professional-support-for-processors-and...

That's why I requested how to reproduce the issue with NXP demo board and SDK demo code.

Jun Zhang

[Kirill_klk]

Sorry for delay. 

The problem was reproduced on OM13090.

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.

Please see the distortion on attached pictures.

[Kirill_klk]

Jun Zhang,

Did you reproduce the issue?

[Kirill_klk]

Jun Zhang,

Did you reproduce the issue?