User manual

GPIO EXPANDER KEYPAD
AND LCD DEMO BOARD
USER’S GUIDE
© 2006 Microchip Technology Inc. DS51636A-page 7
Chapter 2. Installation and Operation
2.1 INTRODUCTION
This chapter discusses the setup and operation of the GPIO Expander Keypad and
LCD Demo Board.
The GPIO Expander Keypad and LCD Demo Board is designed to demonstrate using
GPIO expanders in a keypad and LCD example. The MCP23X17 interfaces to a 2x16
LCD module and the MCP23X08 interfaces to a 4x4 keyed matrix.
Both the I
2
C™ and SPI versions are included on the board to demonstrate both serial
interfaces.
2.2 FEATURES
The GPIO Expander Keypad and LCD Demo Board has the following features:
• Two (2) 8-bit GPIO Expanders
- MCP23008 with I
2
C™ interface
- MCP23S08 with SPI interface
• Two (2) 16-bit GPIO Expanders
- MCP23017 with I
2
C™ interface
- MCP23S17 with SPI interface
• 4X4 keypad layout (16 momentary buttons)
- Numbers 0 - 9
- Six special function buttons
• A 2X16 LCD module
• Headers for the MCP23X08 and MCP23X17 pins
• Header for programming the PIC18F4550