Message buffer full handling in a CAN device that employs reconfigurable message buffers

Abstract

A CAN microcontroller that supports a plurality of message objects, and that includes a processor core that runs CAN applications, a plurality of message buffers associated with respective ones of the message objects, a CAN/CAL module that processes incoming messages that include a plurality of frames, each frame having a maximum number n of data bytes, and a plurality of message object registers associated with each of the message objects, including at least one buffer size register that contains a message buffer size value that specifies the size of the message buffer associated with that message object, and at least one buffer location register that contains an address pointer that points to an address of the storage location in the message buffer associated with that message object where the next data byte of the current incoming message is to be stored. The CAN/CAL module includes a message handling function that transfers successive frames of the current incoming message to the message buffer associated with a selected one of the message objects designated as a receive message object for the current incoming message, a frame status detection function that detects whether or not the current frame of the current incoming message is the final frame of the current incoming message, and a buffer-full detection function. The buffer-full detection function, in response to a detection that the current frame of the current incoming message is not the final frame of the current incoming message, determines the number of available bytes of remaining storage capacity in the message buffer associated with the designated receive message object for the current incoming message, and declares a message buffer-full condition if the determined number of available bytes is less than the maximum number n of data bytes. The CAN/CAL module further includes a message buffer-full interrupt generator function that generates a message buffer-full interrupt to the processor core in response to a declaration of a message buffer-full condition.

Dependencies are inferred from the claim text.