US Patent 7788454 Controller including electrically rewritable nonvolatile memory

A controller includes an internal flash ROM to which initial data is writable after the controller is manufactured. In response to a download enable signal, a download control circuit reads data from an external serial flash ROM in accordance with a set of data read commands stored in a first command register and an address that is registered in an address register. Then, the download control circuit temporarily stores the read data in a data register. The download control circuit writes the data that is temporarily stored in the data register to the internal flash ROM by referring to a set of data write commands stored in a second command register and the address that is registered in the address register.