If I run the SPARTAN 6 at all 2.5V supply (all VCCIO-s, VCCAUX), will the JTAG interface to the DS_FT2232D USB controller work? Four lines of the 'A' port are used for JTAG. The supply voltage to the 'A' port shall be at least 3.0V. So it seems there would be some over-voltage on the TDI, TMS, TCK inputs. Will these inputs accept that? In the design I have "copied" there are 68 Ohms resistors in series with these inputs.