GPIO, the English name is General-Purpose IO ports, which is the general IO port.
There are often many external devices / circuits in embedded systems, but the structure is relatively simple. Some of these devices / circuits need the CPU to provide control means, while others need to be used as input signals by the CPU. Moreover, many such devices / circuits require only one bit, that is, as long as there are two states of on / off, such as lights on and off. For the control of these devices / circuits, it is not appropriate to use traditional serial or parallel ports. Therefore, a "general-purpose programmable IO interface" is generally provided on the microcontroller chip, that is, GPIO.
Difference between GPIO and DIO
DIO is Digital IO, which is called Digital IO
GPIO = DIO
AI / AO is Analog I / O