Interfacing multiple LCDs using two wire interface

LCDs using two wire interface

First thing that comes to the head is why use multiple small LCDs instead of on bigger. But you never know what situation may occur. For this purpose Jesus Echavarria have designed a special board – I2C I/O expander based on MCP23017. It is capable of expanding I2C to 16 I/Os. So he has plenty of these, so why not to try driving 8 LCD using single I2C interface. As driving MCU he uses AT89C51RE2 microcontroller board. Each expander board has its own I2C address by using three jumpers (total 8 possible slaves). The other is left for MCU software to talk to each slave and send LCD commands. I2C interface is more short distance communication interface, so if you wish to connect remote LCDs you may look for different solutions like RS485, CAN etc.   Continue reading