Method for automatically transmitting acknowledge frames in CANopen and other CAN application layer protocols

摘要

A method for use in a CAN device (e.g., a CAN microcontroller) that includes a processor core, for automatically transmitting an acknowledge message. The method includes the steps of receiving a frame of a multi-frame fragmented message, and automatically transmitting an acknowledgment message without requiring any intervention of the processor core, in response to the receiving step. The automatically transmitting step is preferably performed by hardware external to the processor core, e.g., a CAN/CAL module of the CAN device. In a preferred embodiment, the method includes the steps of setting up a first message object having an object number n as a receive message object, enabling the receive message object, setting up a second message object having an object number n+1 as a transmit message object corresponding to the receive message object, storing the acknowledgment message in a response message buffer associated with the transmit message object, receiving a frame of a multi-frame fragmented message, acceptance filtering the received frame to determine that the received frame matches the enabled receive message object, enabling the transmit message object, and automatically transmitting the acknowledgment message, without requiring any intervention of the processor core.