MicroBlaze Development Kit Spartan-3E 1600 Edition User Guide
17
UG257 (v1.1) December 5, 2007
www.xilinx.com
Discrete LEDs
R
UCF Location Constraints
Figure 2-9
provides the UCF constraints for the four push-button switches, including the
I/O pin assignment and the I/O standard used, and defines a pull-down resistor on each
input.
Discrete LEDs
Locations and Labels
The MicroBlaze Development Kit board has eight individual surface-mount LEDs located
above the slide switches as shown in
Figure 2-10
. The LEDs are labeled LED7 through
LED0. LED7 is the left-most LED, LED0 the right-most LED.
Figure 2-8:
Outputs from Rotary Shaft Encoder May Include Mechanical Chatter
A
B
Detent
Detent
UG257_02_0
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Rotating RIGHT
Switch closing chatter on ‘B’
injects false “clicks” to the LEFT
(’B’ rising edge when ‘A’ is Low)
Switch opening chatter on ‘A’
injects false “clicks” to the RIGHT
Rising edge on ‘A’
when ‘B’ is Low indicates
RIGHT (clockwise) rotation
Figure 2-9:
UCF Constraints for Rotary Push-Button Switch
NET "ROT_A" LOC = "K18" | IOSTANDARD = LVTTL | PULLUP ;
NET "ROT_B" LOC = "G18" | IOSTANDARD = LVTTL | PULLUP ;
NET "ROT_CENTER" LOC = "V16" | IOSTANDARD = LVTTL | PULLDOWN ;
UG257_0
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