Patent ID: 7493455

Claim:
A control unit comprising: a non-volatile memory that is rewritable of data electrically; and a processor that normally operates based on a control program and control data, which are defined by data stored in the non-volatile memory, and rewrites the data stored in the non-volatile memory with new data upon receiving a rewriting command from an external device, the new data being sent from the external device, wherein the processor is programmed to receive a rewriting control program for rewriting processing from the external device and store the rewriting control program in a predetermined memory area, which is different from a subject area of rewriting, wherein the processor is programmed to send, after determining that an operation mode is a rewriting mode, a signal indicative of a set baud rate to the external device upon receiving a baud rate value request from the external device under a condition that a baud rate of communication with the external device is set at an initial value, the set baud rate being supportable in the processor and being different than the initial value of the baud rate, wherein the processor is programmed to receive the rewriting control program sent from the external device at the set baud rate and store the rewriting control program in the predetermined memory area, wherein the processor is programmed to be capable of changing, after completing receiving of the rewriting control program, the set baud rate of communication with the external device to a baud rate faster than the set baud rate of communicating the rewriting control program which is executed based on a predetermined change instruction, wherein the rewriting control program includes the predetermined change instruction preceding a set of instructions for executing the rewriting processing.