| 摘要 |
<p>PURPOSE:To omit an external parts (decoder) for selecting a chip and to set up an address range for the assignment of devices optionally by incorporating a circuit optionally generating a signal selecting a peripheral equipment of a microprocessor in an LSI chip. CONSTITUTION:The initial address signals and the last address signals assigned to the peripheral equipment connected to the external terminals 7a, 7d of the microcomputer are stored in registers 6aS, 6aE, 6bS, 6bE, 6nS, 6nE and a signal outputted from a CPU1 to an address bus 2 is inputted to comparators 8a-8n. When these address signals are included in the address range, high level selecting signals CSa-Csn are generated. These selecting signals are outputted to selecting output terminals 9a-9n and supplied to external RAMs, ROMs and I/O chips.</p> |
