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.
This design is distributed under a Creative Commons Attribution-3.0 United States license.
- 24 I/O channels with input protection circuitry
- Adjustable target voltage for level translation: 1.2V to 3.3V
- Supported target interfaces: JTAG/IEEE 1149.1, UART/asynchronous serial
- USB interface for direct connection to host computer
- Product Brief (from Parallax)
- Block Diagram
- Assembly Drawing
- Gerber Plots
- Test Procedure
- Source Code: Parallax Propeller (GitHub)
- Slides: JTAGulator: Assisted discovery of on-chip debug interfaces
- Video: Introduction and demonstration (YouTube)
- Video: UART discovery (YouTube)
- Video: DerbyCon 3.0: JTAGulator full presentation (YouTube)
- Video: Hacker Hotshots: Joe Grand and the JTAGulator (YouTube)
- PCB rev B. on OSH Park
- Poem by Zach Houston