| 摘要 |
<p>PURPOSE:To reduce the circuit scale by constituting the device so that the number (m) of bits of a data temporarily holding means becomes smaller than the number (n) of bits of a successive data input registering means. CONSTITUTION:The number (m) of bits of a data temporarily holding means 12 for registering temporarily a part of serial data DIN=DO-Dn is made smaller than the number (n) of bits of a successive data input registering means 11. Accordingly, an allowance is generated in an installation area of a data holding circuit, therefore, even in the case the number of bits of the serial data DIN increases in connection with a function improving request, etc., of a one chip microcontroller of a user, a ratio of a data input/output device occupied in a chip area is relaxed. In such a way, the circuit scale of a semiconductor chip can be reduced.</p> |
