TheLostSwede Please show me some documentation from Intel that enables user access and instructions on how to interact with GPIOs on any single Intel device. I know of none.

TheLostSwede A parallel port (blinky LED, pfff, I made my own parallel port sound card) or a serial port isn't a GPIO interface.

If you need at least one, here it is:"Custom Solutions Header" is your GPIO.If you've ever disassembled a PoS terminal - those also have a small GPIO breakout(s) which controls various stuff like opening a cash drawer, triggering some external device, or interfacing an SPI credit card reader etc. None of these platforms have "Arduino" soldered in or having a dedicated IC just to handle GPIO, cause it's cheaper to use whatever you already have.If you have a system with exposed non-reserved GPIO, there are ways. On Linux you can get access to SoC/PCH/SuperI/O GPIO via sysfs. If drivers are not existent, then there are some other ways On Windows you would need a vendor-specific GPIO driver (which intel provides for some of their industrial mini-PCs ), or you can hack and slash some Bay Trail or Cherry Trail board, get GPIO off the SoC BGA fanout and run Windows 10 IoT on it (Braswell, Bay Trail, Cherry Trail and others are supported).You can bit-bang any low-speed serial/parallel bus on LPC, you can toggle individual data pins, so it's kida GPIO by definition. Slow and small, but still a GPIO.Your LPT DAC is just an example how GP this I/O actually is.