I want to know how to connect an lcd i2c, with an led 8x8 matrix at the same time. The problem is, all the analog in pins are used, except A0 and A1. Using this tutorial:


It says I must have analog pins A0-A2 with nothing connecting, except I have A2 connected, which is why both screens don't work right. So how can I use only pins A0-A1 with an lcd i2c? Thanks.

1 Answer 1


You may be finding Connect to LCD via I2C, default address 0x27 (A0-A2 not jumpered) confusing. These refer to the I2C address selection lines of the IO expander (the PCF8574T) used on the I2C LCD display and not to the A0-A2 analog pins of the Arduino itself.

Location of address selection jumpers on I2C Adapter

The note // Wiring: SDA pin is connected to A4 and SCL pin to A5. is referring to the analog pins of an UNO (or Nano) because these pins also happen to carry the ATMega328P's I2C ("Wire") signals.

So there's nothing about using the I2C display that prevents you from using the Analog A0-A2 pins of the Arduino for other purposes. Only the Arduino's A4 and A5 pins are used to carry I2C/Wire.

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