The Controller Area Network (CAN) protocol, developed by ROBERT BOSCH GmbH, offers a comprehensive solution to managing communication between multiple CPUs. CAN Specification 2.0 (September 1991) added an extended message format that increases the number of permitted message identifiers. CAN Specification 2.0 is 100% backwardly compatible with the previous CAN Specification 1.2.Several silicon implementations of the CAN protocol are currently available such as the PCA82C200 Standalone CAN-controller from Philips Components, the MC68HC05X4/X16 from Motorola, and the 82526/82527 serial communications controllers from Intel. All of these devices meet the requirements of CAN Specification 1.2. The 82527 serial communications controller from Intel also meets CAN Specification 2.0 requirements including those for the extended message format.This paper compares the differences between CAN Specifications 1.2 and 2.0 and describes the differences between standard and extended message formats. This paper also discusses the architectural features of the PCA82C200, the MC68HC05X4/X16, the 82526 and the 82527 from five perspectives: CAN bus performance, memory size, acceptance filtering, host-CPU interfaces and control/status registers.