| 摘要 |
<p>PURPOSE:To increase the kind of selectable clock signals without increasing the number of input terminals of a control block by providing plural external connection terminals, a converting circuit, a selector, and plural gate circuits on a display control block. CONSTITUTION:A display control block 1 has plural external connection terminals 1a-1d, and is connected to a selector 2. A converting circuit 3 converts a command signal S for designating a clock signal to binary signals S1-S3, supplies S1 and S3 as selecting signals of the selector 2, and also, supplies S1-S3 to the external connection terminals 1a-1c through a gate 4. The external connection terminal 1d is led to an internal display control circuit, as well through a gate 5, and an output of the selector 2 is also led to the internal display control circuit through a gate 6. The gates 4, 5 are opened only when a gate control signal exists, the gate 6 is always opened and it is closed only when the gate control signal exists. Not only a transmitter block 11A but also a transmitter block 11B can be connected.</p> |
