Documentation

1.0 Keypad

The kepad is driven by an io-expander. Thus it can be acessed over i2c. Adress 0x21

1.1 Wiring

• Red: 3.3V
• Black GND
• Green SDA -> D2
• Grey SCL -> D1

2.0 LCD

The LCD display is driven on the same i2c bus as the keypad.

nterface Definition BYTE BIT 7 (MSB) 6 5 4 3 2 1 0 (LSB) I2C slave address L H L L A2 A1 A0 R/W I/O data bus P7 P6 P5 P4 P3 P2 P1 P0