| 摘要 |
PURPOSE:To decrease greatly the number of circuit elements by detecting the coincidence between the row scan signal and the column selection code signal of a key matrix circuit during the timing for push of key buttons. CONSTITUTION:A controller 10 delivers a code selection signal SEL to a code generator 11, and the generator 11 sets the row selection codes M1-M4 and column selection codes N1-N3 showing the positions on a stored key matrix. The codes M1-M4 are inverted I1-I4 and supplied to gates G1-G4, and the coincidence is discriminated between these codes M1-M4 and row selection signals K1-K4 supplied from a key matrix circuit. When the coincidence is obtained for all logics between the signals K1-K4 and the codes M1-M4, the output 13 of an AND gate G5 is set at (1) and then fed to a gate 6. The codes N1-N3 are divided into eight parts by a decoder 12 and connected to gates G7-G14 in the form of column selection signals. Then the outputs selected by gates G7-G14 are delivered to an electronic device, etc. via column selection signal lines L1-L8 in the form of key signals when a key signal output permission signal EN is set at (1). |
