| 摘要 |
PROBLEM TO BE SOLVED: To provide a data processing module having a history function mounted on a CAN module. SOLUTION: The CAN module includes a message buffer 3 capable of buffering a message to be transmitted and a plurality of received messages, a ring buffer 6 capable of storing history information indicating a position in the message buffer 3 where update is performed by as much as a designated number of times, and a message handling section 2 which manages messages in the message buffer 3. The message handling section 2 records position information on update in an arbitrary buffer at a next write position of the ring buffer in such a case and sequentially updates an unread pointer indicating the position of history information in the ring buffer which is not referred to by a CPU according to read access from the CPU. The nearest write position and unread pointer of the ring buffer can be referred to by the CPU, and used to read out the latest message and the oldest unread message. COPYRIGHT: (C)2006,JPO&NCIPI
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