AN432 Datasheet, PDF (1/12 Pages) STMicroelectronics – All members of the ST62 Series of Microcontrollers

AN432
APPLICATION NOTE
USING ST62xx I/O PORTS SAFELY
by J.Stockinger
INTRODUCTION
All members of the ST62 Series of Microcontrollers from STMicroelectronics feature I/O ports
with configurable bit functions. In addition many I/O bits may be set as inputs to the on-chip
Analog to Digital Converter. This port bit function is in addition to the normal I/O functions of
input (with or without internal pull-up resistor), output (open drain or push-pull) or edge/level
selectable interrupt input (with pull-up). This flexibility makes the ST62 series suitable for
many industrial control applications (and for many other uses).
This application note explains the architecture of the I/O bit associated with these port func-
tions and provides some indications on the correct use of these features for functions such as
keyboard scanning and analog inputs. The correct manner to switch between these function is
also demonstrated in order to prevent potential malfunctions in operation.
AN432/1203
Rev. 1.1
1/12
1