Category Archives: Linux

Adafruit I2C RGB 16×2 LCD+Keypad & Raspberry PI

I recently bought one of these

Adafruit RGB Negative 16×2 LCD+Keypad Kit for Raspberry Pi from an Adafruit reseller in the UK (via eBay), for two reasons. 1 to use in my OBDII project, and 2 to learn how they did it (serial to parallel and some 4 bit mangle).

You see the device uses an MCP23017 16bit I2C port extender, and most 16×2 LCD displays require a 4-bit bus (4 data lines) , and an RS, RW and E lines, so i was interested to see how Adafruit were implementing the lcd display protocol over the i2c bus….

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