Microcomputer and processing method of received data

摘要

A first receiving message is stored into a message box and a CPU reads the first receiving message from the message box. Meanwhile, a second receiving message is once stored in the message box and thereafter transferred in direct to a RAM by a DMA controller. The number of times of transfer operation is restricted with an upper limit value. The CPU does not read the second receiving message from the message box but from the RAM and executes the processes based on the message. Generation of failure in the receiving data fetching processes is reduced without physical expansion of the storage regions of the message box.