Bought a Pi3B to run Retropie. I don't own a wired keyboard. I have a logitech K800, which uses a dongle. Please help.
The question is already answered and it is a complete one, but I like to share some more data for those who are interested to know why and how a mouse or keyboard can use USB to communicate with a main hardware(a Pi or a DVR CCTV, a PC or a game console)
As long as your device includes a usb dongle to plug, it will work just like a wired keyboard/mouse.
To install a bluetooth mouse however you will need a driver, which is not the case.
USB defines class code information that is used to identify a device’s functionality and to nominally load a device driver based on that functionality. The information is contained in three bytes with the names Base Class, SubClass, and Protocol. (Note that ‘Base Class’ is used in this description to identify the first byte of the Class Code triple. read more
For instance, Printers base class is 07h and Human Interface Device(HID) like mouse and keyboards both wireless and wired are 03h (base class)
There are two levels of APIs related to USB HID: the USB level and the operating system level. At the USB level, there is a protocol for devices to announce their capabilities and the operating system to parse the data it gets. The operating system then offers a higher-level view to applications, which do not need to include support for individual devices but for classes of devices. This abstraction layer allows a game or a raspian os,... to work with any USB controller even ones created afterward.