March 2007
Rev 2
1/22
UM0300
User manual
Port expander STMPE2401 demonstration board
Introduction
This Document explains the functioning of the port expander demo board consists of the
port expander IC STMPE2401 and controller ST72F63B microcontroller as I
2
C master
along with a PC GUI.
The objective of this demonstration board is to display to the user the features and
capabilities of the port expander chip (STMPE2401) using a Windows-based host software
application and one of several USB low-speed microcontrollers (ST72F63B) from ST acting
as a control device.
The host software and the ST7 source code provide a user friendly environment to use
demo board in following modes:
●
Standalone mode
●
PC GUI mode
In both modes, power to board can be provided from either USB bus itself or from external
power.
In this demo board, the ST72F63B Microcontroller acts as the I
2
C master and controls two
STMPE2401 devices functioning as I
2
C Slaves. The STMPE2401 devices are used to
interface LCD, normal keypad, rotator controller, dedicated keys and 6 PWM outputs. All
these interfaces are controlled by just using I
2
C communication between master and slave
devices.
all events like dedicated key press (four direction keys); keypad key press (4 x 4 keypad),
Rotator direction, power mode etc. are captured and displayed in LCD screen and in the
scan window of PC GUI. For visual display of the PWM output LEDs are provided on the
board. The capability of rotator controller has been demonstrated by mechanically
implementing the rotator configuration using switches.
For interfacing with the PC GUI, the application layer is built above the USB core library that
makes all the hardware control of the USB interface transparent for the developers.
The PC GUI supports various power saving modes of port expander and wake up feature to
get back to default operational mode.
In addition the board has the provision for an alternate I
2
C path for external control.
Also the board has ICC connector to re-program the ST7 Microcontroller flash memory.