How to Use the SH-C30L USB-to-CAN Adapter with Arduino UNO and MCP2515

Controller Area Network (CAN) is one of those technologies that quietly powers a huge number of embedded systems. It is commonly found in cars, EVs, industrial controllers, robotics, and other distributed systems where multiple devices need to exchange data reliably over a shared bus. For development and debugging, it is useful to connect that CAN network to a computer. The problem is that a standard computer communicates through USB, while CAN uses a dedicated differential bus. A USB-to-CAN interface solves this problem by translating between the two. In this project, we will explore the DSD TECH SH-C30L USB-to-CAN adapter , learn how its different firmware modes work, connect it to a PC, and then use an Arduino UNO with an MCP2515 CAN module to create a simple bidirectional CAN communication setup. The goal is not just to make the hardware work, but also to understand what happens between the Arduino, CAN bus, USB adapter, and computer. SH-C30L USB-to-CAN Adapter Overview The SH-C30L is a compact USB-to-CAN interface designed to connect a computer directly to a CAN network. It is based on an STM32F072C8T6 microcontroller, which contains an integrated CAN controller. This allows the adapter to handle CAN protocol processing without requiring a separate external CAN controller. The microcontroller communicates with the computer through USB, while a dedicated CAN transceiver handles the physical CAN interface. The transceiver converts the controller's logic-level signals into the differential CAN_H and CAN_L signals used on a CAN network. One of the interesting aspects of the SH-C30L is its firmware flexibility. The adapter can work with Candlelight firmware , which allows it to operate with Linux SocketCAN and compatible CAN applications, or with SLCAN firmware , where it behaves more like a serial CAN interface. This makes the same hardware useful with different operating systems and software environments. The adapter supports both CAN 2.0A and CAN 2.0B frames, wit