Release [2.1.1] 2025-09-30

[alisitsyn]

Added

• feature fix static analyzer warnings (IDFGH-15453, IDFGH-14651) (079b51e)
• add kconfig value to explicitly enable/disable mdns integration (IDFGH-14828) (f958457)

Fixed

• fix slave accept - open limited connection (IDFGH-15541) (7b2dd25)
• fix slave tcp skips requests from multiple masters (IDFGH-15564) (6dcac67)
• fix master dd allow arbitrary descriptor sizes (Allow arbitrary descriptor sizes without UB #133) (21ae74e)
• fix idf compatibility issues under ci (-) (36b9ab1)
• fix master minor fixes examples and documentation v2 (Bug/Unclear Information when configuring a tcp device as "1:192.168.1.1:502" (IDFGH-15558) #128) (1508be5)
• fix target test issues ut (-) (4daca2f)
• fix fix port serial heap poisoning issue (-) (937e488)
• fix change github actions for jira and project issue prefix to EPROT (-) (6a72cdb)
• fix example tests target issues (addition) (-) (52f7e38)
• fix master FSM multiple error handling (Heap Corruption in Modbus TCP Master after receiving outside of transaction error #135) (58dc8c1)
• fix modbus ci revise idf versions list (-) (7ff65a2)

---

This discussion was created from the release Release [2.1.1] 2025-09-30.

Refer to the latest documentation for main project branch.
The component esp-modbus v2.1.1 in component manager.

[carlos789]

Hello, the MB-TCP-Slave example cannot be compiled.

The error:
CMake Error at C:/Users/carlo_p59mbo7/esp/v5.5.1/esp-idf/tools/cmake/build.cmake:328 (message):
Failed to resolve component 'espressif__esp-modbus' required by component
'main': unknown name.

What would be the cause?
Thank you

[alisitsyn]

Hello,

It is very strange. The component passed build and target tests under CI before release and the examples are build able under all supported IDF versions and functional. I think it is the issue with your environment. In order to find the reason for this I need the whole log the esp-modbus-main/examples/serial/mb_serial_slave/dependencies.lock file and your sdkconfig file.

Update:
I also found your another post here. I guess the issue happens during resolving of component names. Please send me the manifest file C:\ESP32S2\esp-modbus-main\examples\serial\mb_serial_slave/main/idf_component.yml + esp-modbus-main/examples/serial/mb_serial_slave/dependencies.lock. Check if whole esp-modbus component is copied to your esp-modbus-main folder. Otherwise, remove the line override_path: "../../../../" from the manifest file as below:

dependencies:
  idf: ">=5.0"
  espressif/esp-modbus:
    version: "^2"
    override_path: "../../../../" # <<<<<< Remove this line to get component from component manager instead !!!!!!!!!!!!
  mb_example_common:
    path: "../../../mb_example_common" # <<<<<<< check if the folder points to correct place !!!!!!!!!
  protocol_examples_common:
    path: ${IDF_PATH}/examples/common_components/protocol_examples_common 

Please also try to rename the esp-modbus-main of your project folder to something else, for example: esp_modbus_proj. However, I can not reproduce your issue on my linux machine and the most important thing is to change the path in your manifest file to resolve the components correctly.

Unfortunately, this is esp-idf make system constraint. The component folder which is pointed with override_path: should have the name corresponded to registered component name. You need to remove the override_path: and you can move the example to any folder keeping the dependency path for other components. Note: Before compilation please remove the dependencies.lock file from the project folder.

Please let me know about the progress with the above.

Thanks.

[carlos789]

Dear Alex:
Congratulations on the work you've done with the Modbus framework (both slave/master/TCP/Serial). I'm very interested in this development for educational use at my university.
I'm using an ESP32 and an ESP32 S3, and I use ESP-IDF with VSCode on Windows. I'm using the MB_SERIAL_SLAVE and MB_TCP_SLAVE projects.

With the Esp-Modbus-main version 08/27/25
EPS32 and ESP32 S3 boards:
There are no problems compiling both projects. The MB_SERIAL_SLAVE project works fine, but I can't get the MB_TCP_SLAVE project to connect to Wi-Fi.

With Esp-Modbus version 2.1.1 09/30/25
ESP32
Compiling the MB_SERIAL_SLAVE and MB_TCP_SLAVE projects fails, and the following error is printed:

CMake Error at C:/Users/carlo_p59mbo7/esp/v5.5.1/esp-idf/tools/cmake/build.cmake:328 (message): Failed to resolve component 'espressif__esp-modbus' required by component
'main': unknown name.

ESP32 S3
When trying to change the package to ESP32 S3 from VSCode, it fails. The following message appears for the MB_SERIAL_SLAVE project:

Failed to set target esp32s3: non zero exit code 2 Adding "set-target"'s dependency "fullclean" to list of commands with default set of options. Executing action: fullclean Executing action: set-target Set Target to: esp32s3, new sdkconfig will be created. Running cmake in directory C:\Modbus-ESP\esp-modbus-2.1.1\examples\serial\mb_serial_slave\build Executing "cmake -G Ninja -DPYTHON_DEPS_CHECKED=1 -DPYTHON=c:\Espressif\tools\python_env\idf5.5_py3.11_env\Scripts\python.exe -DESP_PLATFORM=1 -DIDF_TARGET=esp32s3 -DCCACHE_ENABLE=0 C:\Modbus-ESP\esp-modbus-2.1.1\examples\serial\mb_serial_slave"... -- Found Git: C:/Espressif/tools/tools/idf-git/2.39.2/cmd/git.exe (found version "2.39.2.windows.1") -- Minimal build - OFF -- The C compiler identification is GNU 14.2.0 -- The CXX compiler identification is GNU 14.2.0 -- The ASM compiler identification is GNU -- Found assembler: C:/Espressif/tools/tools/xtensa-esp-elf/esp-14.2.0_20241119/xtensa-esp-elf/bin/xtensa-esp32s3-elf-gcc...

ESP32 S3
When trying to change the package to ESP32 S3 from VSCode, it fails. The following message appears for the MB_TCP_SLAVE project:

Failed to set target esp32s3: non zero exit code 2 Adding "set-target"'s dependency "fullclean" to list of commands with default set of options. Executing action: fullclean Executing action: set-target Set Target to: esp32s3, new sdkconfig will be created. Running cmake in directory C:\Modbus-ESP\esp-modbus-2.1.1\examples\tcp\mb_tcp_slave\build Executing "cmake -G Ninja -DPYTHON_DEPS_CHECKED=1 -DPYTHON=c:\Espressif\tools\python_env\idf5.5_py3.11_env\Scripts\python.exe -DESP_PLATFORM=1 -DIDF_TARGET=esp32s3 -DCCACHE_ENABLE=0 C:\Modbus-ESP\esp-modbus-2.1.1\examples\tcp\mb_tcp_slave"... -- Found Git: C:/Espressif/tools/tools/idf-git/2.39.2/cmd/git.exe (found version "2.39.2.windows.1") -- Minimal build - OFF -- The C compiler identification is GNU 14.2.0 -- The CXX compiler identification is GNU 14.2.0 -- The ASM compiler identification is GNU -- Found assembler: C:/Espressif/tools/tools/xtensa-esp-elf/esp-14.2.0_20241119/xtensa-esp-elf/bin/xtensa-esp32s3-elf-gcc.exe -- Dete..

The dependencies.lock and sdkconfig files for the MB_SERIAL_SLAVE project are attached.
Thank you very much.
dependencies.lock.txt
sdkconfig.txt

[alisitsyn]

@carlos789,

Thanks for your interest and update. I guess the issue still exists because you probably did not follow the above instruction or some steps are missed. I will try to clarify this. There are several variants to fix the issues. Let us go step by step:

1. Rename the folder C:\Modbus-ESP\esp-modbus-2.1.1 to C:\Modbus-ESP\esp-modbus.
2. Push keys: Windows key + R, then type cmd; cd C:\Modbus-ESP\esp-modbus\examples\tcp\mb_tcp_slave in your terminal window.
3. delete dependencies.lock file.
4. delete C:\Modbus-ESP\esp-modbus\examples\tcp\mb_tcp_slave\build folder or type command: idf.py fullclean.
5. This should work now for your S3 board: idf.py set-target esp32s3
6. idf.py menuconfig.

7. `idf.py build` and wait while the compilation is completed, there should not be any error. 8. `idf.py -p /dev/ttyUSB#YourPort flash monitor` 10. You should see the log like below:

I (3456) wifi:connected with YourSSID, aid = 1, channel 3, 40U, bssid = 64:d1:54:1a:23:5b
I (3456) wifi:security: WPA2-PSK, phy: bgn, rssi: -27
I (3456) wifi:pm start, type: 1
I (3456) wifi:dp: 1, bi: 102400, li: 3, scale listen interval from 307200 us to 307200 us
I (3466) wifi:AP's beacon interval = 102400 us, DTIM period = 1
I (7976) esp_netif_handlers: example_netif_sta ip: 192.168.99.254, mask: 255.255.255.0, gw: 192.168.99.1
I (7976) example_connect: Got IPv4 event: Interface "example_netif_sta" address: 192.168.99.254
I (7986) example_common: Connected to example_netif_sta
I (7986) example_common: - IPv4 address: 192.168.99.254,
I (7996) wifi:Set ps type: 0, coexist: 0
I (8206) mdns_mem: mDNS task will be created from internal RAM
I (8206) port.utils: hostname set to: [mb_slave_tcp_ca36fc]
I (8206) port.utils: mdns delegate hostname set to: [mb_slave_tcp_01]
I (8216) port.utils: IP: 192.168.99.254
I (8216) port.utils: GW: 192.168.99.1
I (8226) port.utils: NETMASK: 255.255.255.0
I (8236) port.utils: Socket (#54), listener  on port: 1502, errno=0
I (8236) mb_port.tcp.slave: loop:0x3ffc99f0  mbs_on_ready: fd: -1, bind is done
I (8296) SLAVE_TEST: Modbus slave stack initialized.
I (8296) SLAVE_TEST: Start modbus test...

Means the tcp slave is listening on port 1502 on the address 192.168.99.254. So, you should be able to connect to 192.168.99.254:1502 using your modbus master application and configure it accordingly to access the slave register areas. Alternatively you can use the master example and configure it appropriately as described in the readme file.Please refer to the instructions in the slave tp example, master tcp readme.

Alternatively, you can delete the line override_path: "../../../../" from C:\Modbus-ESP\esp-modbus\examples\tcp\mb_tcp_slave\main\idf_component.yml and follow the steps above from step 2. The build folder and dependencies.lock file from example folder should be deleted before compilation.
If you have any issues please delete the dependencies.lock, build folder and sdkconfig file, follow env setup: %IDF_PATH%\export.bat and try again.

[carlos789]

Hi Alex:
Thank you very much for your help and patience.
I was able to successfully compile the MB_TCP_SLAVE project for the ESP32 S3 board, but I'm still having the problem of not connecting to my WiFi.
My SSID is Casa 2.4 and the password is Santa3V5F. When I enter menuconfig, I set them as follows:
In ${CI_WIFI_SSID} I type "Casa 2.4" and
in ${CI_WIFI_PASSW} I type "Santa3V5F." Is this okay?
Thank you very much, sorry for the inconvenience, and best regards.
Carlos

[alisitsyn]

Hi, Carlos,

It seems you passed the SSID and Pass correctly. The ~~${CI_WIFI_PASSW}~~ needs to be removed, please make sure the credentials are ok for your AP). Once you set it correctly and your AP is able to accept connection, you will see the messages like below in your slave app terminal:

I (1688) example_connect: Connecting to Casa 2.4...
I (4508) wifi:connected with Casa 2.4, aid = 1, channel 3, 40U, bssid = 64:d1:54:12:56:5b
I (5688) esp_netif_handlers: example_netif_sta ip: 192.168.100.250, mask: 255.255.255.0, gw: 192.168.100.1
I (5728) example_common: - IPv4 address: 192.168.100.250,
I (6158) port.utils: hostname set to: [mb_slave_tcp_cc36fc]
I (6168) port.utils: mdns delegate hostname set to: [mb_slave_tcp_01]
I (6168) port.utils: IP: 192.168.100.250
I (6178) port.utils: GW: 192.168.100.1
I (6178) port.utils: NETMASK: 255.255.255.0
I (6348) port.utils: Socket (#54), listener  on port: 1502, errno=0
I (6358) mb_port.tcp.slave: loop:0x3ffcb5dc  mbs_on_ready: fd: -1, bind is done
I (6448) SLAVE_TEST: Modbus slave stack initialized.
I (6448) SLAVE_TEST: Start modbus test...

After this the slave is waiting for connection from your Modbus master. Please check your network settings on both sides to make the connection to the AP. Refer to WIFI AP, STA examples from esp-idf for more information.
P.S. If you need help could you create new issue for this here. This will allow to track and provide answer for this faster. Thank you.

[carlos789]

Hi Alex:
Thank you for your kindness and help. I'm following your advice and will add my problem to Git issues, due to a lack of connection to the Wi-Fi network in the MB_TCP_SLAVE example.
Best regards
Carlos