| 摘要 |
PURPOSE:To obtain the best memory area for various systems by providing RAM slaves newly and easily expanding a RAM area for storing the data of a master. CONSTITUTION:The RAM slaves 103 and 103R are added newly and the RAM slave 103R has a CPU 212 and a RAM 122 and has a corresponding memory area. Further, the data of the master 101 are held in the RAM 122 of the RAM slave 103R. Then when a CPU 111 reads out the data in the RAM 122, the CPU 111 sends a read command to the RAM slave 103R and sends the address data in the area of the RAM 122 where the data to be read out to the RAM slave 103R. The CPU 121 of the RAM slave 103R reads the data out of the address of the RAM 122 specified with the sent data and sends the data to the master 101 through a receiving interface 104 and a serial transmission line 102. Consequently, the memory can be increased or decreased with the small- sized and low-cost constitution. |
