WIFI Issues with ESP32-S3-WROOM-1 modules that don't have a CMIIT ID

[tonystuart]

I use generic ESP32-S3-DevKitC boards as a sub-assembly in a product. These boards have an ESP32-S3-WROOM-1 module on them. I source them from a number of suppliers.

On some of these boards the WIFI doesn't work properly. It successfully scans for Access Points, but won't connect to an Access Point. In the following photo, the board on the left doesn't work. The board on the right works.

ESP32-S3-DevKitC-WIFI-Issues.2024-09-18a.jpg (93.56 KiB) Viewed 12429 times

I found an earlier topic that describes a problem with being able to scan for Access Points but not connect:

viewtopic.php?t=32109

This earlier topic suggests touching the WIFI antenna with a finger while connecting. This works with my problem boards as well.

Looking at my boards carefully, I see a pattern. The boards that don't work have different markings on the ESP32-S3-WROOM-1 module than those that do work. In particular, the CMIIT ID is empty on the boards that don't work.

Also the onboard antenna on the non-working board on the left looks like a typical Meandered Inverted F Antenna (MIFA) while the antenna on the working board on the right has an extra meander.

I am using Full RF Calibration as described here:

https://docs.espressif.com/projects/esp ... ation.html

And here are the WIFI PHY settings from my sdkconfig:

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CONFIG_ESP_PHY_CALIBRATION_AND_DATA_STORAGE=y
# CONFIG_ESP_PHY_INIT_DATA_IN_PARTITION is not set
CONFIG_ESP_PHY_MAX_WIFI_TX_POWER=20
CONFIG_ESP_PHY_MAX_TX_POWER=20
CONFIG_ESP_PHY_REDUCE_TX_POWER=y
CONFIG_ESP_PHY_ENABLE_USB=y
# CONFIG_ESP_PHY_ENABLE_CERT_TEST is not set
# CONFIG_ESP_PHY_RF_CAL_PARTIAL is not set
# CONFIG_ESP_PHY_RF_CAL_NONE is not set
CONFIG_ESP_PHY_RF_CAL_FULL=y
CONFIG_ESP_PHY_CALIBRATION_MODE=2

This leaves me with a number of questions:

• Are ESP32-S3-WROOM-1 modules produced only by Espressif or by many suppliers?
• What does the missing CMIIT ID mean? Is this an early version of the board? Should it even be available?
• Is there a way to configure the WIFI or PHY to work around this problem?

Any ideas?

Thanks!

[MicroController]

• Is there a way to configure the WIFI or PHY to work around this problem?

On some -C3 "Supermini" boards I found that I had to actually reduce the WiFi TX power from the default (20dBm?) (used esp_wifi_set_max_tx_power()) to be able to connect to a network. Probably due to a "sub-optimal" matching network and/or antenna on the board. IIRC, I could only go up to 11 or 13dBm before connection issues appeared. May be worth trying out.

[tonystuart]

Thanks... I'll give that a try.

Update: I tried reducing the max tx power and it connects. Very interesting... and a bit counterintuitive (at least for me)!

[DahBenni]

I also had the same issues and wanted to try esp_wifi_set_max_tx_power(40);
Then I found this post: https://esp32.com/viewtopic.php?t=41895

I simply started to unsolder / disconnected an external LED from GPIO Pin 21.
Surprise: It resolved my issues instantly

[nhandt64]

I have the exact same custom board like you on the right, which also have CMIT ID. It however doesn't connect to my home Wifi as expected while the original ESP32 custom board just connect without any hassle.

I'm working with Arduino IDE + arduino-esp32 because I'm new to mcu programming in general, and I thought if the board is defected, or libraries doesn't really working (I have thought about switching to esp-idf but my college project doesn't give me abundant amount of time).

I spent almost a day getting this sorted out and finally I came to this post, what a relief (and funny).

I'm not sure about the GPIO soldering solution, but for now I think I just need to touch the Wifi antenna XD

[seba2122]

I have the same issue? Did you ment to solve it? I have 4 of ESP S3 Chips with the same issue , they only connect when the transmission power is lowered. Is it a board design issue?

[sorek_]

I am a bit mad at this because I ordered quite big chunk of ESP32-S3 and it's first time I have such problem with ESP32 ever..

For me using `esp_wifi_set_max_tx_power(40)` (or lower) doesn't solve anything, I basically have to have access point created on my phone next to the device and it connects once every 8 times which is bad (setting lower power doesn't solve that really).

Connection to home wifi is impossible while old board (violet) has no issues and does that usually within 500 ms (I have timout that waits for connection after .begin() and then fallsback to access point).

AP works good, and once device is connected to STA (or AP) it can maintain fast and stable connection even across two rooms - but still I have no clue what is happening there.

I noticed my ESP module only differs in single number of back of antenna, other than that (hard to show on pictures) faulty modules seems to have much worse etching on the front.

Not sure what to do at the moment as anything I try to do doesn't seem to work and wifi scan of network shows the same powers on both boards (within 2-3 db error).

[fabrizioPucci]

Hello, I have 6 internally produced boards with the same ESP32S3 Wroom 1 device.
Some of them can easily connect to the PC hotspot, and some can't.
I tried reducing power, touching the antenna, and many other strategy and nothing worked.
Then I tried to use the Samsung S22 2.4GHz hotspot, and now, after being connected to the Samsung HotSpot, all of them are working fine.
In the past (if I remember correctly), I think that I have read something related to an internal memory with some wifi related parameters that could create some problem, and after the corrected connection, they have been fixed.
Anyway, I cannot find it again, so maybe my experience is related to something else.

[pbruening]

Hello, thanks for the hints with max power and touching the antenna. They work for the modules I ordered which have the same design as shown in the initial post. I would like to know if the PCB layout can be responsible for this or is it the ESP32-S3 module? The modules are delivered with PCB antenna, so the reason should not be the hardware design around, correct? Moreover, I did not find any hints in the datasheet that could explain this situation based on custom hardware design. Are there any official statements from Espressif? I am working on a mass production product and would like to know if an ESP32-S3 can be used without expecting massive problems on connectivity.. As long as this is not clear, I won't use this module.

[sorek_]

Seems like this command helped:

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esp_phy_erase_cal_data_in_nvs();