Last Modified: September 11, 2012
No, you do not have to re-program your MAX II device if you are powering a bank with a different VCCIO than has been set in your project assignments and previously programmed into the device. MAX II devices have one I/O buffer which behaves according to specification as determined by the VCCIO setting. The drive strength setting, however, is controlled by programming. If you want to change the drive strength setting from maximum to minimum, or vice versa, the device has to be re-programmed with that setting. For example, if a device is programmed with I/Os in bank 1 assigned to 3.3V LVTTL and maximum drive strength, but is powered on the board by VCCIO = 2.5V, then the I/O buffers will perform as specified by 2.5V operating conditions with maximum current strength for 2.5V LVTTL.