Contents
What is Aref Arduino?
AREF means Analog REFerence. It allows us to feed the Arduino a reference voltage from an external power supply in order to configure the reference voltage used for analog input (i.e. the value used as the top of the input range).
What does pin 0 RX mean?
Analog Reference pin (orange) Digital Ground (light green) Digital Pins 2-13 (green) Digital Pins 0-1/Serial In/Out – TX/RX (dark green) – These pins cannot be used for digital i/o (digitalRead and digitalWrite) if you are also using serial communication (e.g. Serial.
What is Aref atmega?
The Aref pin is used for an external voltage reference. If you attach it to 5V then you can’t attach it to an external reference voltage. With it disconnected you can program the pin to internally connect to 5V. The capacitor is just for decoupling and noise reduction when using it as a real voltage reference pin.
What is the IORef pin used for on an Arduino board?
IOREF. This pin on the Arduino/Genuino board provides the voltage reference with which the microcontroller operates. A properly configured shield can read the IOREF pin voltage and select the appropriate power source or enable voltage translators on the outputs to work with the 5V or 3.3V.
What is Arduino UNO rev3?
Arduino Uno is a microcontroller board based on the ATmega328P (datasheet). It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header and a reset button.
What is the PIN number of Aref in atmega8?
ATMEGA8 Pin Configuration
| Pin No. | Pin name | Description |
|---|---|---|
| 19 | PB5 (SCK) | Pin5 of PORTB |
| 20 | AVCC | |
| 21 | AREF | |
| 22 | GND |
Can a AREF pin be connected to an external voltage?
The internal voltage reference options may not be used if an external reference voltage is being applied to the AREF pin. From the Arduino reference pages: Alternatively, you can connect the external reference voltage to the AREF pin through a 5K resistor, allowing you to switch between external and internal reference voltages.
When to switch from Aref to internal AVCC?
The application would benefit from the increased resolution of switching to 1.8V AREF when sampling the 1.8V sensors and switching to the internal AVCC reference for the 5V sensors.
What does the AREF pin do on a mbed?
It Configures the reference voltage used for analog input (i.e. the value used as the top of the input range). For Mbed Nano Boards there is no AREF pin on the microcontroller and the only references to be used with the ADC are the internal ones. So in the MBED boards, the AREF pin is not connected to anything.
Can a external reference voltage be used on an ATmega328?
From the ATMega328 datasheet, section 24.9.1: The internal voltage reference options may not be used if an external reference voltage is being applied to the AREF pin. From the Arduino reference pages: