Durham University, Durham, United Kingdom
CCFE, Abingdon, Oxon, United Kingdom
York University, Heslington, York, United Kingdom
On MAST (the Mega Amp Spherical Tokamak) at Culham Centre for Fusion Energy some key control systems and diagnostics are being developed and upgraded with FPGA hardware. FPGAs provide many benefits including low latency and real-time digital signal processing. FPGAs blur the line between hardware and software. They are programmed (in VHDL/Verilog language) using software, but once configured act deterministically as hardware. The challenges in developing a system are keeping up-front and maintenance costs low, and prolonging the life of the device as much as possible. We accomplish lower costs by using industry standards such as the FMC (FPGA Mezzanine Card) Vita 57 standard and by using COTS (Commercial Off The Shelf) components which are significantly less costly than developing them in-house. We extend the device operational lifetime by using a flexible FPGA architecture and industry standard interfaces. We discuss the implementation of FPGA control on two specific systems on MAST. The Vertical Stabilisation system comprises of a 1U form factor box with 1 SP601 Spartan6 FPGA board, 10/100 Ethernet access, Microblaze processor, 24-bit σ delta ADS1672 ADC and ATX power supply for remote power cycling. The Electron Bernstein Wave system comprises of a 4U form factor box with 2 ML605 Virtex6 FPGA boards, Gigabit Ethernet, Microblaze processor and 2 FMC108 ADC providing 16 Channels with 14-bit at 250MHz. AXI4 is used as the on chip bus between firmware components to allow very high data rates which has been tested at over 40Gbps streaming into a 2GB DDR3 SODIMM.
Durham University, Durham, United Kingdom
CCFE, Abingdon, Oxon, United Kingdom
ESRF, Grenoble, France
Merton College, Oxford, United Kingdom
York University, Heslington, York, United Kingdom
FPGAs are now large enough that they can easily accommodate an embedded 32-bit processor which can be used to great advantage. Running embedded Linux gives the user many more options for interfacing to their FPGA-based instrument, and in some cases this enables removal of the middle-person PC. It is now possible to manage the instrument directly by widely used control systems such EPICS or TANGO. As an example, on MAST (the Mega Amp Spherical Tokamak) at Culham Centre for Fusion Energy, a new vertical feedback system is under development in which waveform coefficients can be changed between plasma discharges to define the plasma position behaviour. Additionally it is possible to use the embedded processor to facilitate remote updating of firmware which, in combination with a watchdog and network booting ensures that full remote management over Ethernet is possible. We also discuss UDP data streaming using embedded Linux and a web based control interface running on the embedded processor to interface to the FPGA board.