A 10K resistor should go between the input pin and VCC. If you are working on pins A6/A7 you cannot access the internal pull-up resistor, so you need to add your own to prevent a floating input. You should connect the pin with a pull up resistor - for arduino pins A0-A5 (depending on board, i'm referring to a Nano) this can be done internally using: pinMode(5, INPUT_PULLUP) // Enable internal pull-up resistor on pin 5 But to answer the question, yes you can read analogue input, which is useful on pins like A6/A7 which cannot be used as digital pins. Is it possible to read the value of the switch in the analog in pinsĪs other answers say, you can use digitalRead on most Analogue pins. An actual push button circuit with Arduino Uno. In any case, given an analog reading ar, and letting CPS be the expected step in counts from one switch to the next (in this case either 256/5 or 1024/5 depending upon use of 8 or 10 bits of readings), compute switch number via something like s = (ar+CPS/2)/CPS. Thats why you need a pull-up or pull-down resistor in the circuit. In some systems, a fast reading may be good enough by itself to decode switch number if not, take a second reading via ordinary analog read. ![]() One would first use a fast analog read (about 13 μs) to decide if any switch is pressed for example, if the first reading is above 1/2 V. You get 0 V at A6 when all the switches are open. With this circuit attached to A6, you would get 1 V at A6 when you press S1 2 V when you press S2 3 V when you press S3 and so forth. However, you can use a circuit like the following to multiplex several buttons. A6 and A7 on an Uno or Nano is limited to analog input. ![]() A5 have standard digital capabilities, but A6 and A7 do not. On ATmega48A/PA/88A/PA/168A/PA/328/P devices (with Arduino Uno using an ATmega168- or 328-family device) analog inputs A0. They can be used to read or write digital values, like other digital pins on the device. Toggling case using pushbutton and ++ should be a very very simple matter. Case 0 could be 5 presses and be the last cycle using the ++x operator. 1 press would be case 1, 2 press - case 2, 3 press - case 3, etc. On ATmega640/ATmega1280/ATmega1281/ATmega2560/ATmega2561 devices (with Arduino Mega using an ATmega640 or 2560), the analog input pins have their analog capabilities in addition to standard digital capabilities. Another though would be to utilize switch (case) by modulo, toggling case values by pressing the button a specific number of times.
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