On-chip debug (OCD) interfaces can provide chip-level control of a target device and are a primary vector used by engineers, researchers, and hackers to extract program code or data, modify memory contents or affect device operation on the fly. Depending on the complexity of the target device, manually locating available OCD connections can be a difficult and time-consuming task, sometimes requiring physical destruction or modification of the device.

JTAGulator is an open-source hardware tool that assists in identifying OCD connections from test points, vias, or component pads on a target device.

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