发明授权
US5554985A Method for scanning keypad architecutre employing power source and ground of digital electronic devices 失效
使用数字电子设备的电源和地面扫描键盘控制的方法

Method for scanning keypad architecutre employing power source and
ground of digital electronic devices
摘要:
A scanning method of keypad architectures utilizing power pin V.sub.DD and ground pin GND of an integrated circuit device is disclosed. The integrated circuit device has a number of row pins and column pins, a power pin and a ground pin, and a number of pins for other functions of the integrated circuit device. The row and column pins, power pin and ground pin of the integrated circuit device are connected to respective connections of a keyswitch matrix, which has a plurality of row connections and column connections. The keyswitch matrix of the scanning apparatus has a first one of the row connections connected to the power pin. The keyswitch matrix of the scanning apparatus has a second one of the row connection connected to the ground pin. Each of the other row pins is connected respectively to corresponding one of the row connections. Each of the column pins is connected respectively to corresponding one of the column connections. The scanning scheme is employed to identify the row and column of the key having its key switch depressed. A keyswitch matrix having a total of (M-2)+(N-2) integrated circuit device pins can have a maximum of (M.times.N)-4 keys in the keypad.
公开/授权文献
信息查询
0/0