AN2421使用键盘控制器STMPE801只

AN2421使用键盘控制器STMPE801只

AN2421
Application note

Using the STMPE801 as a keypad controller

Introduction
STMPE801 is an 8-bit general purpose port expander device in the STMicroelectronics Port
Expander Logic family. Its eight GPIOs (General Purpose Input Output) are connected to the
host system using a standard I2C connection.
This application note explains how to control an 8*8 (64-key) matrix keypad using the 8
internal GPIOs of a base-band processor and the 8 GPIOs of the STMPE801 port expander.
The simplified schematic is shown below.

Schematic for