ESP32 Forum

In one of my project I am using Moddable Nimble on ESP32S3. Please find details/configurations about project as below.

Moddable version - 4.0
ESP-IDF version - 4.4

I am using android nrf connect app to test with ESP32S3. I have created characteristic with write and notify properties on ESP32S3.
I am facing issue that after updating MTU size from nrf connect mobile application, I am not able to write on characteristic and after some seconds mobile app initiates disconnection (may be due to GATT timeout or any other issue).

I am able to change MTU size and able to write characteristic at very first time after ESP32S3 bootup. So, very first time issue is not observed. But, if I perform connection-disconnection cycle and perform connection again, update MTU size, after that I am not able to write on characteristic.

I have done configuration (CONFIG_BT_NIMBLE_ATT_PREFERRED_MTU = 256) to update MTU size to 256 on ESP32S3. I have put prints in ESP32S3 firmware and verify whether BLE client is receiving correct MTU value on ESP32S3 or not. I observed that when this issue occurs, ESP32S3 receives MTU value as 0 instead of 256.

If I don't update MTU size then I am able to write and notify characteristics successfully, but payload response has max 20 bytes only.

Can you please check and let me know why I am facing this issue? Any ESP configurations are needed to solve this?

Can anyone have response on this?

Probably not. I suggest asking the people behind the moddable SDK, or in a moddable community. If you do, you'll probably want to share your code for people to check if the problem is in your code or in the moddable SDK.

We have contacted moddable community. They suspect that esp-idf might be responsible for this issue as they run moddable demo code and try to reproduce the issue. But, they are not able to reproduce the issue and it is working fine. So, they think that moddable is not responsible for this issue and asked us to test with latest esp-idf.

Earlier we were using esp-idf 4.4. Now, we have started working with esp-idf 5.1.0.

Can you please help us by checking that is there any fix incorporated between mentioned esp-idf releases?