Multiport Remote JTAG Over Optical Fibers Under Radiation Environment

The Joint Test Action Group (JTAG) protocol is a popular method to program field-programmable gate array (FPGA) devices where a more intelligent technology is not applicable. However, the original JTAG protocol is designed for a short-distance connection and is not necessarily suitable when the FPGA device is located in a remote radiation area. We developed a custom optical transmission technique for the JTAG protocol. A small receiver test board is developed based on discrete devices, and a multiport distributor is implemented on an FPGA board. We also developed a technique to overcome the latency due to serialization and cable length. We present the evaluation results and future applications.