MICRO COMPUTER

摘要

PROBLEM TO BE SOLVED: To contribute to preventing the deterioration in the control performance by eliminating the omission of communication data without directly expanding the memory area in a data memory means called a message BOX. SOLUTION: A message having relatively low processing priority which is sorted by the filter pattern of a mask 1 in a filter circuit 16c is stored in an area No.'14' in a message BOX 16a. A DMA controller 17 monitors a transmission/reception state 16e to transfer the message stored in the controller 17 to a RAM 15. The transfer is repeated every time a new message is stored until the number of transfers of a register 17i reach the upper limit stored in a register 17c. A CPU 13 reads the message stored in the area '14' in the message BOX 16a out from the RAM 15 to carry out processes on the basis of the message.