Jetson Nano + I2S audio AMP ( MAX98357A) pop noise issue

Autonomous Machines Jetson & Embedded Systems Jetson Nano
1

Dear Sir ,

     We use MAX98357A I2S audio amplifier with Jetson Nano . When playing music , there are two pop noise , one is happened before music start  , the other is at end of music delayed 4 seconds .

     Playing the same music at MAX98357A EVB ( USB to I2S (DSP board) + MAX98357A (Amplifier board) ) , there is no such pop noise . 

     From the " pop noise .jpg " image , We found the pop noise happened at around the beginning of LRCLK signal , but if repeat play the same music immediately , ther is no pop noise . 

     In the MAX98357A EVB , without play music , ther still are BCLK / LRCLK waveform , in jetson Nano ,  BCLK / LRCLK are present only when play music . 

     Can this problem be fixed by  modifying the I2S driver to send the BCLK / LRCLK waveform always ?

BR
Wayne

pop noise.jpg
pop noise.jpg2016×1512 870 KB

MAX98357A circuit.JPG
MAX98357A circuit.JPG1501×582 76.9 KB

2

Hi Wayne,

Please refer to troubleshooting doc to see if can help: https://docs.nvidia.com/jetson/l4t/index.html#page/Tegra%2520Linux%2520Driver%2520Package%2520Development%2520Guide%2Fasoc_driver.17.2.html%23wwpID0E0VD0HA

3

Hello Wayne,

Can you try adding a 100ms pop delay to see if this has any improvement …

$ echo 100 | sudo tee /sys/kernel/debug/asoc/tegra-snd-t210ref-mobile-rt565x/dapm_pop_time

100ms may not be necessary, but at least this will indicate if adding a delay when switching on the DAPM widgets helps or not.

Regards,
Jon