摘要 |
PURPOSE:To simulate the push of a key system switching key without changing a keyboard driver in order to evade the complicated processing of an application program, by outputting a shift code in case a key code system is modified. CONSTITUTION:A code deciding circuit 1 supplies a code 200 when an input request signal 100 is turned on and compares the code 200 with the code supplied previously by a step. If a difference is detected between both codes, a shift code output request signal 300 is outputted to a code output control circuit 2 and a shift code generating circuit 3. At the same time, the input code 200 is outputted to the circuit 2. The circuit 2 holds the code 200 by an internal buffer and outputs nothing to outside as long as the signal 300 is outputted. Here the circuit 3 outputs a shift code 400 equal to the one that is outputted with push of a switching key to an OR circuit 4. Thus the circuit 4 outputs the code 400.
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