| 摘要 |
<p>PURPOSE:To prevent penetration current and to lower power consumption by setting outputs to floating state and fixing inputs to an L level at the time of power-down mode in a two-way circuit to an I/O port. CONSTITUTION:In a CMOS input/output circuit that transmits information in two ways between an I/O port pin terminal and an internal data bus, a controlling signal C of H level is inputted to an output controlling circuit 204 and an input controlling circuit 208. Both P and N MOS transistors of an output buffer 202 off, and the I/O port 1 becomes a floating state. The output signal of an input controlling circuit 208 is made forcibly to the L level by the controlling signal C of H level. THus, the penetration level does not flow even when the potential level fluctuates, and lowering of power consumption is made possible.</p> |
