Before ROSCON 2013 I did similiar things. I implemented a lightweight ROS in C. Had also an IMU demo with an STM32F4 board ;-) ... I posted this in the SIG embedded, but did not have any time to maintain it. So how ready is your stuff (I will have a look into repo later) ? Do you also have a code generator for standard ROS message generation in C (as single header file, like me did)? I used standard serial (RS-232 or USB) to communicate between uC and PC, and managed to use the available ROS-Serial pc-node to use my uC.
Regards,