1. At temperature governing system, key pad can be applied operator to enter set point temperature wanted
2. At motor governing system, key pad can be applied operator to enter set point speed of motor wanted
3. At officer absence system, key pad can be applied for officer to enter the ID, etc.
There is many key pad types which able to be found marketing. We will take example of keypad module interface 4x4 that drawing the physical shown to this figure;
Figure1
First Pace, we construction soybean cake of the hardware must, or minimum of the characteristic. Unknowingly construction hardware or characteristic a peripheral, we are not possible to be made interface program MCU to peripheral. If you had known construction hardware and this module characteristic, please directly make a bolt for second steps. If it is disassemblied this module depth and depicted is its schematic diagram, hence us will get in this figure;
Figure2;
There is 16 fruit of nipple pushbutton stringed up in such a way so becomes 4 column lane (K1,K2,K3,K4) and 4 battery lane (B1,B2,B3,B4). From this construction, we can get the characteristic data is as follows:
1. Otherwise there are emphase of nipple at all, hence all lanes would be each other disengaged (nothing that is jointed)
2. There is no one condition enabling the happening of joint between column lane humanities or between battery lane humanities, except there are emphasis of nipple multiple. For example; nipple 1 and nipple 2 depressed to be at the same, hence K1-K2-B1 will be jointed.
3. For emphasis only one nipples, hence only happened joint between column lanes and battery lane that is connected at nipple depressed the. For example, if nipple 1 is depressed, hence K1-B1 will be joint. Data as complete is for emphasis every nipple can be seen tables.
Because at most application only be required detection to emphasis of one nipples only, so in the next will be studied handling to emphasis of one just nipples and disregards emphasis of nipple multiple. Flowchart work we are
Flowchart:
