Hi ! I found this morning a super affordable development board with a very nice Single/Dual ARM-9 and a small integrated FPGA. I am enthusiast because it enables anyone to build a new class of electronic devices that was really difficult to make on your own.

What is a FPGA ?

FPGA enables to build you own digital hardware, it uses an interconnect network linking together different kind of so-called "slices" such as: memory, flip-flops, logics, io, analog and dsp. You use a hardware description to describe your digital hardware such as Verilog, VHDL. You compile, simulate, test and after you load your hardware design to the FPGA.

Standalone FPGA cost

Typically the problem is when you want to communicate to an microprocessor/microcontroller, you need to develop in general this on the FPGA and it is a lot of effort where you need to know a lot of stuff : software driver programming, communication protocol layers, hardware knowledge. It is not very accessible.
While with an integrated FPGA with the CPU, vendors put a direct access through memory in general (and additional features that are vendor specific).

It means that the software driver development is greatly simplified because you can use the memory to send and receive data. Also, it provides a huge performance advantage, you do not have to cross all those additional communication layers and you can reduce to the minimum the amount of slices that are used for the communication on your FPGA.

What kind of applications ?

Typically anything that needs a throughput higher than your micro-controller can sustain and/or when you need a very low latency to control something for instance. It is an enabler to further creativity.
For instance, for robotics, you want to have a closed loop to control your motors very tightly in order to be sure that the move you want to perform is really the one that is performed (CNC, 3DPrinters ...) such device will enable it at a low cost.
For music, you can build directly the hardware of some vintage synthesizers, experiment cheaply and quickly.

Super Affordable ARM-9+FPGA

The board is called: Z-turn Lite

Check out the link : http://www.myirtech.com/list.asp?id=565

It features a Xilinx XC7Z007S or XC7Z010, for around 100$ you have a full development kit with the XC7Z010 which is a Dual Core ARM-9 with an integrated FPGA. There is a small IO extension board too that enables HDMI, Camera, LCD and a lot of IOs for 30$.

Overview of the Xilinx Zynq 7000: https://www.xilinx.com/support/documentation/data_sheets/ds190-Zynq-7000-Overview.pdf

Additionally, on this platform there is a dedicated dual port SRAM of 256KB for low latency communication between the CPU and the FPGA fabric. Also it has 2 fast 12-bit ADC with 1M samples per sec, with a multiplexer allowing up to 17 external analog inputs.