Before revision: 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.Special Microcontroller Functions, retrieved 29 October 2011 Specialized functions can include: Hardware interrupts, analog input or output PWM output Serial communication
After revision: , such as UART, USART, SPI bus, or SerDes.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.Special Microcontroller Functions, retrieved 29 October 2011 Specialized functions can include: Hardware interrupts, analog input or output PWM output Serial communication