I'm going to interface a 5V CMOS DSP to the 3.3V Flex 6000 FPGA.
This FPGA supports 3.3V and 5V IO according to the below figure from the datasheet:
Since the FPGA I found in stock is the 3.3V version, I must connect VCCINT and VCCIO to 3.3V. The minimum Vih of the DSP is 2V. Is it safe to connect both devices together? I'm afraid this 1.3V (3.3V - 2V) isn't enough to avoid ripples or ringing effects on the signals.