| 摘要 |
<p>PROBLEM TO BE SOLVED: To effectively use a RAM for a data memory provided in a microcomputer originally when transmitting and receiving USB data to/from a host, and to reduce the chip size of the microcomputer. SOLUTION: The data area 42 of the RAM 40 can be used as a data memory area to be controlled by a CPU 70 when an address signal ADR2 is selected. The area 42 can be used also as a data memory area for storing program data (32 bit unit) from a USB interface circuit 30 temporarily when an address signal ADR1 is selected. The data area of the RAM 40 can be accessed from both of the CPU 70 and the circuit 30.</p> |
