| 摘要 |
<p>PURPOSE:To drastically delete the number of an I/O port required for and address of an external ROM by providing an address error detecting section, plural serial buffers and a CPU hold control section. CONSTITUTION:An address error detecting section of a program counter 1 is connected to a serial buffer 5 and a CPU hold control section 9, and to the control section 9, an address error detecting signal fed from the address error detecting section is inputted. Thereby, the control section 9 stops a feed of an internal clock of a microcomputer and temporarily stops all operations of the microcomputer except for buffers 5 and 8 at that time condition. The control section 9 stops its operation by a signal from the buffer 8 and releases the feed stop of the internal clock. In this manner, by providing the address error detecting section, the buffers 5 and 8 and the control section 9, the number of an I/O ports required for the address can be drastically deleted.</p> |
