| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor integrated circuit device including a general microcomputer capable of obtaining the same effect as that in containing a mask ROM without containing the mask ROM for storing a program, a system using the device and developing technology for it. SOLUTION: The microcomputer 100 is formed by circuits such as a CPU 1, a serial flash interface circuit 2, a program transfer circuit 3, a built-in RAM 4 for a program, and a write mask circuit 5. An external serial flash memory 200 is connected to the outside of the microcomputer 100, and when the power is applied, before the CPU 1 operates, the program is read from the external serial flash memory 200 and written to the built-in RAM 4 for the program, and the CPU 1 can execute the program on the built-in RAM 4 for the program. Writing to the built-in RAM 4 for the program can be inhibited at need. |
