AN2591 Datasheet, PDF (1/19 Pages) STMicroelectronics – In certain applications

AN2591
Application note
Microcontroller input / output expander
Introduction
In certain applications, the number of input and/or output lines available in the
microcontroller you have chosen may be too small and this may lead you to select another
microcontroller in order to have enough I/Os to meet your application needs. In some cases
this choice means you have to use a more expensive part.
However it may often be better to look for a solution that allows you to add more I/Os and
still use the microcontroller you selected originally.
This application note shows how to use a simple technique to increase the number of inputs
and/or outputs.
August 2007
Rev 1
1/19
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