To link a standard 16×2 LCD directly with the microcontroller, for instance Arduino, you would need atleast 6 I/O pins to talk to the LCD. However, if you use an LCD module with I2C interface, you ...

To communicate with each LCD via I2C, two TCA9548A I2C multiplexers are connected to an Arduino, along with an RTC to keep track of the time and date itself. As the TCA9548A has three pins ...

It uses a one-time programmable microcontroller and the RDA1846 transceiver. With the power traces to the MCU cut, [Lior] was able to send his own signals to the chip over I2C using an Arduino.