| 摘要 |
PURPOSE:To obtain the controller of the data holding circuit which uses a microcomputer having a small number of input/output ports by using a time- division output signal for supplying a digit signal of a display body even as the output signal for data hold control of the data holding circuit. CONSTITUTION:A scanning signal output from an output port A supplies the digit signal of the display body 2 through a driving circuit 12 to supply a data holding command to data holding circuits 3-6. When data is held at the fall of a scanning signal, data of output ports D at falls of pulses of respective A-1- A-4 are held by the data holding circuits. Data (0, 1, 0, 1) of the output port D are held at the fall timing of A-1. Similarly, data (1, 0, 1, 0) of the output port D are held at the fall timing of A-2, data (0, 0, 0, 1) of the output port D are held at the fall timing of A-3, and data (1, 1, 0, 0) of the output port D are held at the fall timing of A-4. |
