DEVICES.................| VOLTAGE..| STANDARD.| DESCRIPTION ................................| (VCC)..........|......................| ================================================================ XC4000...................|.......5...........|.....TTL............| 0: A logic Low in TTL (A/D/H/L/E/EX).....|....................|.......................| should be < 0.5 Volts. Spartan....................|....................|.......................| A pull-down of 4.7KOhm is XC3000 (A/L)..........|.....................|.......................| recommended. XC5200...................|.....................|.......................| 1 : A logic high in TTL should be > 4.0 Volts. A pullup of 3.3KOhm is recommended. ================================================================= XC4000X.................|......3.3..........|....LVTTL........| 0: A logic Low in LVTTL (XL/XLT/XLA/XV)...|.....................|.......................| should be < 0.5 Volts. Spartan-XL..............|......................|.......................| A pull-down of 4.7KOhm is recommended. ................................|......................|.......................| 1 : A logic High in LVTLL should be > 3.0 Volts. A pullup of 3.3KOhm is recommended.