18
MicroBlaze Development Kit Spartan-3E 1600 Edition User Guide
www.xilinx.com
UG257 (v1.1) December 5, 2007
Chapter 2:
Switches, Buttons, and Knob
R
Operation
Each LED has one side connected to ground and the other side connected to a pin on the
Spartan-3E device via a 390
:
current limiting resistor. To light an individual LED, drive
the associated FPGA control signal High.
UCF Location Constraints
Figure 2-11
provides the UCF constraints for the four push-button switches, including the
I/O pin assignment, the I/O standard used, the output slew rate, and the output drive
current.
Related Resources
x
Rotary Encoder Interface for Spartan-3E Starter Kit (Reference Design)
http://www.xilinx.com/s3estarter
http://www.xilinx.com/sp3e1600E
Figure 2-10:
Eight Discrete LEDs
LED7
LED0
S
partan-
3
E
Development Board
UG257_02_10_061
3
06
Figure 2-11:
UCF Constraints for Eight Discrete LEDs
NET "LED<7>" LOC = "A8" | IOSTANDARD = LVTTL | SLEW = SLOW | DRIVE = 8 ;
NET "LED<6>" LOC = "G9" | IOSTANDARD = LVTTL | SLEW = SLOW | DRIVE = 8 ;
NET "LED<5>" LOC = "A7" | IOSTANDARD = LVTTL | SLEW = SLOW | DRIVE = 8 ;
NET "LED<4>" LOC = "D13" | IOSTANDARD = LVTTL | SLEW = SLOW | DRIVE = 8 ;
NET "LED<3>" LOC = "E6" | IOSTANDARD = LVTTL | SLEW = SLOW | DRIVE = 8 ;
NET "LED<2>" LOC = "D6" | IOSTANDARD = LVTTL | SLEW = SLOW | DRIVE = 8 ;
NET "LED<1>" LOC = "C3" | IOSTANDARD = LVTTL | SLEW = SLOW | DRIVE = 8 ;
NET "LED<0>" LOC = "D4” | IOSTANDARD = SSTL2_I ;
UG257_02_11_062106