I have a simple VHDL file which can be simulated correctly and that synthesizes with Quartus II-11.0 (web edition). I can interact with switches,leds, seven segments and push buttons.
My problem is that among the 9 Altera DE2 boards I have, only 3 of them behave as expected. The FPGA seems the same...
Visually however, there are little differences on the two kind of boards, but I cannot understand why they don't behave the same :
I am using exactly the same bitstream (pof or sof).
What I am missing ? Where can I find the exact info about these differences ?