For development purposes, embedded platforms are usually accessed through a JTAG or an SWD interface. Through these communication channels, it is possible to upload the software onto the flash of the target, and access the on-chip debug functionalities. There are several self-contained JTAG/SWD adapters on the market that can be controlled through USB from the host, while some development boards are equipped with an extra chip controlling the JTAG channel, that connects to the host through USB.
A powerful generic open source tool to access JTAG/SWD functionalities on the target is the Open On-Chip Debugger (OpenOCD). Once properly configured, it creates local sockets that can be used as a command console and for the interaction with the debugger frontend. Some development boards are distributed with additional interfaces to communicate with the core...
