Serial portsĪ port is the generic name with which we name interfaces, physical or virtual, that allow communication between two computers or devices.Ī serial port sends the information through a sequence of bits. Therefore, the serial port is a fundamental component of a large number of Arduino projects, and it is one of the basic elements that we must learn in order to take full advantage of Arduino. There are endless possibilities in which the use of the serial port is required. Thanks to the serial port we can, for example, move the mouse Serial ports are the main way to communicate an Arduino board with a computer. The 10 bits of resolution means that it will map input voltages between 0 and 5 volts into integer values between. The arduino Nano has 8 analog inputs, each of them provides 10 bits of resolution. ADCĪn Analog to Digital Converter (ADC) is a very useful feature that converts an analog voltage on a pin to a digital number. PotenciometerĪ potentiometer is a simple knob that provides a variable resistance, which we can read into the Arduino board as an analog value. check if the pushbutton is pressed.For this activity you must remember the concepts shown below. read the state of the pushbutton value: Lastly, an example of reading the input: const int buttonPin = A7 // the number of the pushbutton pinĬonst int ledPin = 13 // the number of the LED pin 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. 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. 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. 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.
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