Hello,
We are Ecurie Aix, the Formula Student team from the RWTH Aachen. We design and manufacture a fully electric race car to compete in Formula Student competitions against teams from other universities from around the world. For our electronics we design and use many different PCBs throughout the entire vehicle which are all kindly supported by AISLER. One such board is our USB CAN interface which is presented in this article.
The board presented here is a simple 2-layer PCB and was developed as a compact, reliable interface for communication between the CAN bus in our vehicle and USB. At its core sits a STM32G0 which is simple but powerful enough for this relatively simple task and additionally makes it compatible with the open-source candleLight boards and firmware.
During development, special emphasis was placed on electrical safety because of the presence of the 600 V tractive system in our vehicle. For this reason, the board features additional galvanic isolation with an insulation strength of 3 kV. This ensures that even in the worst-case scenario involving a vehicle fault, the up to 600 V cannot be transmitted to the laptop or the user.
In addition, the board features switchable termination. A switch located on the side allows the 120-ohm termination to be easily enabled or disabled depending on the application scenario. This increases flexibility in practical use and simplifies integration into various test and vehicle environments. For the actual CAN interface, we used a TCAN1472 transceiver from Texas Instruments, which supports high data rates with CAN FD and, most importantly, CAN FD SIC (Signal Improvement Capability). This means that even in less-ideal scenarios we can reliably use the device for debugging.
The result is a compact and versatile board that does exactly what it needs to, does it safely, and does it reliably. Additionally, with ENIG finishing, the silkscreen isolation barrier, and the general quality of the board, it looks great doing it.
