We purchased a Terasic C5G FPGA board + FX3 Explorer Kit + Altera HSMC adapter board. According to Terasic's manual the voltage standard for the signals on the HSMC port is 2.5V. But on the FX3 Explorer Kit I can only select either 1.8V or 3.3V (with jumper J2). I already tried to find an answer in the Explorer Kit's manual but was unable to. The question is: What to do? Is the FX3 Explorer board 2.5V tolerant when set for 1.8V I/O operation? Afaik the C5G board is not 3.3V tolerant for 2.5V I/Os, right?
Thanks for your reply. On the C5G board the I/Os of the HMSC-port are fixed at 2.5V and can't be changed. But after reading the Cyclone V's datasheet it "seems" that specifically at 2.5V the I/Os are 3.3V tolerant. I've tested this and it didn't destroy my FPGA, so apparently this is the way to do it.