I didn't find a lot articles with making artificial neural network on FPGA, only just reviews. So my question: is it possible? If it is - is it hard? why there is a few articles about it - may be it is too easy?
Not only it is possible, but probably using FPGAs for ANNs is the best way because of their extremely high level of parallelism which may outperform any MCU/DSP on the market.
I vote for what was recommended by Mohamad Hanif Md Saad - he pointed to a valuable resources.
Yes... it is the best option if you want to implement an ANN on any hardware. Due to parallelism in FPGA (i.e. FPGAs can process the inputs at a time unlike the sequential i.e. one-by-one execution behavior of Microprocessors and Microcontrollers), ANN can be built up with more ease with faster and efficient outputs.