PURPOSE: To eliminate the need for an additional circuit by providing plural switching elements deciding the characteristic of input and output and a changeover device selecting any of the switching elements and programming the state in the case of logic programming so as to attain a programmable input output characteristic.
CONSTITUTION: When the logic is programmed to turn on pull-up/pull-down changeover devices 1, 2 respectively, pull-up/pull-down are conducted via pull-up/ pull-down resistors 1, 8 by programming the pull-up/pull-down simultaneously. Furthermore, an input signal is terminated by controlling the devices 1, 2 to be both turned on. Moreover, a resistor is inserted in series with an input signal by controlling an input resistor changeover device 3 to be turned on. Furthermore, either of buffers 5, 6 is selected by controlling an input buffer changeover device 4 to revise an input level. Thus, the programmable input output characteristic is attained.
SEKIBE TSUTOMU
KAJIMURA TOSHIYUKI
SUGIMOTO HIROKO
