Development of a processor embedded timing unit for the synchronized operation in KSTAR

Highlights: • Timing board for the synchronized tokamak operation. • Processor embedded distributed control system. • Single clock source and multiple trigger signal for the plasma diagnostics. • Delay compensation among the distributed timing boards. - Abstract: The Local Timing Unit (LTU) in KSTAR provides a single clock source and multiple trigger signals with flexible configuration. Over the past seven years, the LTU had a mechanical redesign and several firmware updates for the purpose of provision of a robust operation and precision timing signal. Now we have developed a third version of a local timing unit which has a standalone operation capability. The LTU is built in a cabinet mountable 1U PIZZA box and provides twelve signal output ports, a packet mirroring interface, and an LCD interface panel. The core functions of the LTU are implemented in a Field Programmable Gate Array (FPGA) which has an internal hardcore processor. The internal processor allows the use of Linux Operating System (OS) and the Experimental Physics and Industrial Control System (EPICS). All user level application functions are controllable through the EPICS, however the time critical internal functions are performed by the FPGA logic blocks same as the previous version. The new LTU provides pluggable output module so that we can easily extend the signal output port. The easy installation and effective replacement reduce the efforts of maintenance. This paper describes design, development, and commissioning results of the new KSTAR LTU.