This figure summarizes the layers of a CAN-based solution. The physical bus is at the bottom. Above that is the CAN peripheral. At the top are the firmware layers consisting of the CAN API driver and the application. From an application source code point of view, one would like to interface only with a simple CAN Application Programming Interface, or CAN API, and not have to bother with details of the CAN peripheral registers. Such an API has been developed by Renesas for the RCAN-ET peripheral, and is virtually the same API as used for the M16C family of MCUs. This simplifies moving applications between platforms. The layer between the CAN API and the application is not at all necessary, but may be used depending on the industry type a product belongs to. However, it is not discussed in this presentation.