| 摘要 |
<p>PURPOSE:To efficiently use a single chip microcomputer in which universal software is stored by changing a memory address position where the program start address information of the single chip microcomputer is stored. CONSTITUTION:When a mode signal MD is set at '0', two bits counting from the most significant order of a PC (program counter) 10 are set and remaining bits are reset by a reset signal, then, an address goes to 4000H. When the reset signal RESET is canceled, a microprogram is operated, and the contents of addresses 4000H and 4001H are fetched as the content of the PC 10 finally, then the execution of the program is started. Since the addresses 4000H and 4001H exist in an external memory area, the program can be executed from an appropriate address without performing a write processing on an internal ROM. Such state is valid for the pre-write of the universal program in the internal ROM in the single chip microcomputer and the usage of the microcomputer as a universal microcomputer.</p> |
