Special input/output explained

Special input/output (Special I/O or SIO) are inputs and/or outputs of a microcontroller designated to perform specialized functions or have specialized features.

Specialized functions can include:

• Hardware interrupts,
• analog input or output
• PWM output
• Serial communication, such as UART, USART,^{[1] [2]} SPI bus, or SerDes.
• External reset
• Switch debounce
• Input pull-up (or -down) resistors
• open collector output
• Pulse counting^[3]
• Timing pulses^{[4] [5]}

Some kinds of special I/O functions can sometimes be emulated with general-purpose input/output and bit banging software.

See also

• Atari SIO

References

1. Book: Advanced PIC Microcontroller Projects in C . 357 . Dogan Ibrahim . 2011 . 9780080558424 . Elsevier Science.
2. Development of Smart Card Door Access Control System . Adetoyi . O.E. . 2017 . International Journal of Electronics Communication and Computer Engineering . 8 . 1 . 41–44.
3. Book: Embedded Robotics; Mobile Robot Design and Applications with Embedded Systems . 61 . Thomas Bräunl . 2013 . 9783662050996 . Springer Berlin Heidelberg.
4. Book: Arduino Microcontroller Processing for Everyone! . 265 . Steven F. Barrett . 2013 . 9781627052542 . Morgan & Claypool Publishers.
5. The STM32 microcontroller based pulse intensity registration system for the neutron monitor . Shepetov . A. . Chubenko . A. . Kryakunova . O. . Nikolayevsky . N. . Salikhov . N. . Yanke . V. . 2017 . EPJ Web of Conferences . 145 . EDP Sciences.