| 摘要 |
<p>PURPOSE:To make an external circuit unnecessary to simplify peripheral circuits of a microcomputer and to reduce the number of parts by using one terminal as a serial signal input terminal and a serial signal output terminal and directly connect this terminal to a serial bus. CONSTITUTION:If a serial signal 105 outputted from a serial transfer means 104 synchronously with a shift clock 103 is in the high level in case of serial transmission, an MOSFET 106 is made conductive and the first potential 107 is outputted to a serial bus 109 from a serial signal input/output terminal 108. If the signal 105 is in the low level then, the FET 106 is made non-conductive and the second potential 111 is outputted to the serial bus 109. In case of serial reception, a transmitted signal is taken input the serial transfer means 104 through an input buffer 101 synchronously with the clock 103 is serial transfer information is set to the serial transfer means 104 so that the signal 105 is always in the low level.</p> |
