| 摘要 |
The circuit for using common controll port of the key and LED to increase the number of key and LED in the key system without changing the peripheral circuit comprises an one-chip microprocessor (10), a transistor array circuit 920) for receiving the scanning signal through the common port, a LED driving circuit (30) for driving the LED with a driving signal from the microprocessor, a LED matrix circuit (40) for displaying the LED with the control signal of the array circuit, a switching circuit (50) for protecting the current flowing to the key while driving the LED, and a key matrix (60) for providing the control signal to the microprocessor.
|
