【应用笔记】使用MAX II和MAX3000A器件扩展微控制器I/O口(Using MAX II & MAX 3000ADevices as a Microcontroller I/O Expander)
Many microcontroller and microprocessors limit I/O ports and pins to
conserve pin counts and reduce package sizes. For many microcontroller-
(e.g., PIC, 8051, and SX) or microprocessor-based systems, the system
design requires more I/O pins without changing the microcontroller. To
increase the number of I/O pins without changing the microcontroller,
I/O expansion provides a solution. With up to 272 I/O pins and
MultiVoltTM I/O capability, Altera® MAX® II and MAX 3000A devices
allow you to implement microcontroller I/O expansion in
microcontroller- or microprocessor based systems. This application note
explains how to implement a microcontroller I/O expander in MAX II
and MAX 3000A devices.an265.pdf