Patent ID: 7640371

Claim:
An integrated circuit having a CPU for downloading a program from another integrated circuit via serial communication and executing the program, wherein: the integrated circuit comprises an interface circuit for judging that a format of reception data is modified if the interface circuit is set in a specific mode and judging that the format of reception data is normal if the interface circuit is not set in the specific mode, and extracting the program from the reception data when the reception data containing the program is downloaded and received from the above-mentioned another integrated circuit, wherein the interface circuit comprises: a transmission memory for storing transmission data to be transmitted to the above-mentioned another integrated circuit during a normal mode; a reception memory for storing the program contained in the reception data received from the above-mentioned another integrated circuit during the normal mode; and a timing control circuit for carrying out control such that, during the normal mode, the program contained in the reception data received from the above-mentioned another integrated circuit is stored only in the reception memory and that, during the specific mode, the program contained in the reception data received from the above-mentioned another integrated circuit is stored in both of the transmission memory and the reception memory.