Program update system and electronic device with program update function

摘要

A manufacturing cost of an integrated circuit chip used in a program update system or in an electronic device with program update function is reduced. A first integrated circuit chip has a USB interface circuit, a compression decoder, a CPU and a mask ROM. The first integrated circuit chip is a single chip consolidating a microcomputer with a USB host function and the compression decoder. A second integrated circuit chip has a CPU and an FROM, and serves as a system microcomputer to control the whole system of a car audio. A control program stored in the mask ROM is updated using the FROM incorporated in the second integrated circuit chip.