The Xilinx evaluation boards such as the ML605 (Virtex-6), KC705 (Kintex-7) and VC707 (Virtex-7) give access to high end FPGAs for a relatively low budget. Actually the cost of these boards is about the same as you’d pay if you wanted to buy just the FPGA on the board itself, so essentially you are getting all the other features such as USB, memory, Ethernet, PCI-Express interface, etc. for free. A very interesting use for these boards is in combination with analogue to digital or digital to analogue converters (ADCs and DACs). The FMC form factor has grown rapidly in popularity giving a huge range of high performance modules. The Xilinx evaluation boards listed above can all take up to two such FMC modules. This makes an extremely powerful processing platform. Below you can see a Xilinx KC705 Kintex-7 Evaluation Board and a 4DSP FMC150 ADC/DAC Daughter Module. We have a lot more FMC modules available.
Xilinx Evaluation Board Problems
The main disadvantage is that the PCBs are on the large side and when FMCs are mounted and the board is placed in a PCI-Express slot of a standard PC or workstation, it is no longer possible to close the system. The analogue cables are also positioned in an awkward position, protruding further from the open door. This makes such systems very fragile and liable to damage should a cable be accidently pulled or an item fall into the open computer.
To provide a solution we have come up with a 1U 19” rack platform that can house a Mini-ITX motherboard, Xilinx evaluation board in a PCIe 16x slot via riser, hard drives and FMC modules. Short analogue cables are used to connect the FMC analogue connectors to the front panel. This has the secondary advantage of allowing use of larger, more robust and convenient SMA connectors in place of the customary SSMC or MMCX of the FMC modules. The power supply is an external laptop style unit rated at 120W which is more than sufficient.
400Mbytes/second Storage to a Single Drive
In the photographs you can see a system with a 4DSP FMC108 8 channel 250MHz ADC. Using a single SSD we can acquire and store data at more than 400Mbytes/second sustained. Furthermore we can elect to do some of the processing on the CPU.
OpenCL and General Purpose GPU on Intel CPU
Using latest Intel Core CPUs we have good OpenCL performance. This allows us to make use of the rapid development possibilities of a GPU and CPU and put say complex image processing here and leave simpler pre-processing tasks to the FPGA. This flexibility can be a huge benefit during proof of concept stages when algorithms are changing frequently. In my next post I’ll look at some code and show how we bring FPGA board, Intel CPU and storage together.