Hi Gianluca,
i measured the Sampling frequency with an oscilloscope and its indeed 2 Msps.

I also made a measurement with a pwm signal of 120 kHz and a duty cycle of 90%. As you can see on the picture it is pretty much 2 Msps.

Hi Guys,
i had to update from esp-idf version 4.1 to 4.2. Now everything is working as it should.
For further questions check out this post: https://github.com/espressif/esp-idf/pull/1991

With the following code (quite messy) I am able to get realistic adc readings up to a frequency of 10 ksps however as soon as i increase the sampling rate over 10 ksps the adc-readings are all zeros again. #include "freertos/FreeRTOS.h" #include "freertos/event_groups.h" #include "esp_log.h" #includ...

I have already tried both .apll=true, and apll=false, without any difference.
As input I use a cosine wave with a frequency of about 400Hz for testing purposes. I have also used constant values of 2.0V, but the adc display remains zero.

Hi Gianluca,

You are right that doesn't make sense in my code. I changed it according to your suggestions.

The problem unfortunately remains the same.

Hi Gianluca, thanks for your reply, I tried several sampling rates from 3 kHz to 100 kHz but it didn't work for any of them. I am using the esp-idf version 4.1. Here is the code that I used. I reused quite a lot of Your code. #define TAG "I2S" #define SAMPLE_RATE 5000 #define I2S_UNIT (0) #define DM...

Hey tasun2000,

ita been some time but maybe I can help you out.
what exactly is your problem?

Hi, i'm facing a quit similar problem. I try to take adc measuremets with the maximum possible sample rate. In the Documentation I read something of about 2 Msps. However, I can't get the i2s_adc_dac- example to work. When i read from the DMA buffer i always get zeros. I also tried your Example @Gia...

Hi,
I know this post is quite old, but i have the same problem. I am using esp-idf version 4.1 and i can't get the i2s_adc_dac-example to work.

Whenever the sample frequency is over 5 kHz the i2s_read()-Function returns only zeros.

Is there any known solution for this problem?

Hi,

if anyone still has a similar issue, i solved mine in https://www.esp32.com/viewtopic.php?f=13&t=18763

Kind Regards