Event Scheduled CAN (ESCAN) is a new, open sourced, scheduling protocol for CAN. The aims of the protocol are discussed, including the ability to optimise the available bandwidth over CAN and enable maximum bus loading as well as providing a worst case determinism for message reception. A number of potential applications for the protocol are covered as well as details of how ESCAN can be used to optimise existing higher layer protocols such as CANopen and
J1939. A comparison with TTCAN is also discussed, including the benefits of ESCAN in terms of CPU utilisation, ROM and RAM requirements and the potential for cost savings that that brings while still providing the advantages of TTCAN.
These advantages include a simple to implement basic protocol stack, no specialist hardware requirements needed to support the protocol other than a TTCAN compliant CAN controller (this is so that the retransmission of CAN frames can be disabled). The protocol also uses a low amount of overhead to transmit its schedule control data resulting in high potential bus loading at all CAN bit rates.
An initial implementation of the protocol stack is used to gather preliminary performance data so that the advantages over TTCAN can be demonstrated.