Re: FPGA classification
Xilinx, Altera, Actel, Atmel, Cypress, Lattice, Minc and Quiklogic are FPGA vendors. In other words, they are some companies which produce and sell different FPGA products and boards. Each of them has lots of products. For example Altera has FLEX series, Apex series and ... products and Xilinx has XC series, Virtex series, Spartan and ... products. As you know, to work with a hardware we need some softwares to synthesize and program the hardware. Some of them have own softwares to program the FPGAs and set up the hardware. For instance MAX-PLUS II and Quartus are software tools which are presented by Altera company. You can use synthesis tools to synthesize the HDL code to a FPGA based design. In orfer to synthesize the HDL code, different synthesis tools including Leonardo and Synopsys's synthesis tool can be used. When you select to synthesize based on FPGA, you can see different products from different vendors. As i mentioned before, some of FPGA vendors have a specific synthesis tool, like MAX-PLUS II of Altera Company.
Regards,
KH