There are differences in hardware or software between nrf52832 I2S and nrf52840 I2S？？？

[xingye123]

  

The picture is the audio data processed by software, which is driven from nrf52832 and nrf52840. The first audio is the data of nrf52832, which is normal. The second audio is the data of nrf52840, which has a lot of noise, but can also hear a little sound faintly. All operations are the same, including the code. I don't know where the problem is, which leads to the problem of the data of nrf52840, I hope your company's gods help

[awneil]

have you compared the descriptions in the two Product Specifications ?

In your 2nd trace, it looks like it keeps jumping to negative-max ("minus infinity") - maybe you have a problem with word size, signed/unsigned, sign-extension, or similar ... ?

EDIT

Maybe try sending a triangle wave with amplitude from -1 to +1 - and see what that tells you ... ?

[Kenneth]

There should be no difference I can think of.

Can you check if the buffers are word aligned? Something like:

__ALIGN(4) static uint8_t audio_data[N]; 

[xingye123]

Thank you for your reply. I also feel very strange. The codes are all the same, and not all nrf52840 can work. I can hear some noises,

[Kenneth]

Please do check that the buffers are word aligned if you haven't already. Also compile with debug (not release), because the i2s driver should throw error if you init or buffers are wrong, this will not be checked if you are compiling with release. For difference between DEBUG and RELEASE see this reply:
https://devzone.nordicsemi.com/f/nordic-q-a/73037/glitch-in-analog-audio-output-when-using-i2s-module/306523#306523 

Also check out this finding:
https://devzone.nordicsemi.com/f/nordic-q-a/73037/glitch-in-analog-audio-output-when-using-i2s-module/306463#306463 

You can also try to place the I2S buffers in a different RAM block (different AHB bus), though I don't expect your problem is related congestion on the AHB bus between several peripherals:
https://infocenter.nordicsemi.com/topic/ps_nrf52840/memory.html 

[xingye123]

Another problem is that when I turn on I2S to read data, the while loop does nothing, and the broadcast can't be transmitted, just like I2S has occupied all the CPU, and other codes can't be executed,