Most FPGAs support JTAG.

1. What is JTAG?
2. How JTAG works
3. Query the JTAG chain
4. Run a boundary-scan

This project comes with a tutorial source code written in C to be used with a Xilinx parallel-III or Altera ByteBlasterMV/II cable.
Get it here.

Links

• A JTAG Boundary Scan presentation from TI (PDF).
• A Boundary Scan Tutorial from ASSET InterTech, Inc. (PDF).
• Boundary-Scan Testing in Altera Devices.
• The SVF Format for Xilinx Devices.
• The AP-630 from Intel.
• The SVF specification from ASSET and TI.

• JTAG 1 - What is JTAG? ❯