Parallax Inc JTAGulator, Debugger, Programmer

On-chip debug (OCD) interfaces can provide chip-level control of a microcontroller device and are frequently used to extract program code or data, modify memory contents or affect device operation while it is running. 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.