Microcomputer system reading data from secondary storage medium when receiving upper address from outside and writing data to primary storage medium

摘要

When a serial external interface receives a port address from a host device, a CPU reads data at all device addresses corresponding to the port address from a secondary storage medium and writes the data to a primary storage medium. When receiving a device address from host device, serial external interface transmits the data stored in primary storage medium and corresponding to the device address to host device. Therefore, it is possible to transmit the data to host device in short time after receiving the lowest address.