Micro-ROS timer not working on my esp32 board/toolchain

Hey! I have some issues getting the micro-ROS timers working on my ESP32, from the micro-ROS publisher example for platformIO: https://github.com/micro-ROS/micro_ros_platformio/tree/main/examples/micro-ros_publisher.

I understand that the supported boards for ESP32 are the esp32dev with the espressif32 platform. Unfortunately, due to the drivers for the servos I am trying to run, I am forced to configure my platformIO environment with the nodemcu-32s board and the espressif32@2.0.0 platform (I am unable to read or write to the bus servos without this). Hence, my environment setup in my platformio.ini file is the following:

[env:nodemcu-32s]
platform = espressif32@2.0.0
board = nodemcu-32s
framework = arduino
monitor_speed = 115200
lib_deps = 
    madhephaestus/lx16a-servo@^0.9.3
    https://github.com/micro-ROS/micro_ros_platformio
board_microros_distro = humble
board_microros_transport = serial

when it should be:

[env:esp32dev]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
lib_deps = 
    madhephaestus/lx16a-servo@^0.9.3
    https://github.com/micro-ROS/micro_ros_platformio
board_microros_distro = humble
board_microros_transport = serial

I intend to use the timers to publish the servo positions at a set rate.

• Hardware description: ESP32dev board (ESP32 devkitC), Ubuntu 22.04 on WSL
• Installation type: ROS2 Humble Hawksbill installed using https://docs.ros.org/en/humble/Installation.html and microROS installed as per https://micro.ros.org/docs/tutorials/core/teensy_with_arduino/.
• Version or commit hash: humble

I have been able to create regular publishers and subscribers that work, but I am unable to use the timers. When I run the ros agent with the platformIO setup as first shown, the timer publisher topic appears, but does not publish (it never enters the timer callback). However when I run the micro-ros agent with the environment set up as in the second instance, the publisher topic both appears and contents are published to the topic.

It appears as though it is an issue with the board setting i.e. board = nodemcu-32s or board = esp32dev in the .ini file, since when I alter the platform, without altering the board setting, the publisher still does not give the expected outcome. However, I am unable to use board = esp32dev since the toolchain/platform I require (espressif32@2.0.0) is not available for this board.

Is there something I can perhaps change in the header files, or at a lower level to get timer functionality working on the older board and platform?

Help would be greatly appreciated.

Start with the examples/micro-ros_publisher example and compare the two platformio.ini environments described in the issue. Reproduce the timer behavior with the nodemcu-32s board and espressif32@2.0.0, then determine whether the timer callback runs; done means timers publish as they do with the esp32dev configuration.