In this paper we propose a method to develop low-cost training FPGA-based boards for fast prototyping of digital circuits aiming ease of use. This method allows the implementation of prototyping boards targeting all Xilinx FPGA families including SPARTAN-III and VIRTEX-II PRO. The board configuration is carried out in serial mode (master and slave) through a microcontroller, although JTAG is also supported by some of our final designs. RS-232 serial mode configuration makes board programming independent on the OS platform in use. Daisy-chain configuration is feasible for those designs that require multiple FPGAs interconnected.
We present examples of different training boards intended for academic laboratories that support a wide range of SPARTAN, VIRTEX and VIRTEX-E FPGA devices. The implementation cost of the boards is in average a 50% of the cost of alike commercial products.