Debug port

A debug port is a diagnostic interface (akin to a computer port) included in an electronic system or integrated circuit to aid design, fabrication, development, bootstrapping, configuration, debugging, and post-sale in-system programming. In general terms, a debug port is not necessary for end-use function and is often hidden or disabled in finished products.

When constituted in a high availability or safety critical system, a debug port may continue to operate as a system monitor for integrity validation in the finished product. In low-cost or high-volume electronics, debug ports are sometimes left enabled to avoid costs of design changes, and can be used by modders and hackers to gain control of the device or access to extra functionality. To avoid this, some manufacturers may choose to add passkey which needs to be sent over the debug port first before accessing the functionality, and this passkey usually is known only to the manufacturer and/or authorized entities like service/repair centers.