Digilent 410-044-10P-KIT - Manual (Page 19)

Spartan-3 Starter Kit Board User Guide www.xilinx.com 19
UG130 (v1.1) May 13, 2005 1-800-255-7778
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Chapter 4
Switches and LEDs
Slide Switches
The Spartan-3 Starter Kit board has eight slide switches, indicated as in Figure 1-2 . The
switches are located along the lower edge of the board, toward the right edge. The switches
are labeled SW7 through SW0. Switch SW7 is the left-most switch, and SW0 is the right-
most switch. The switches connect to an associated FPGA pin, as shown in
Table 4-1 . A
detailed schematic appears in Figure A-2 .
When in the UP or ON position, a switch connects the FPGA pin to V
CCO
, a logic High.
When DOWN or in the OFF position, the switch connects the FPGA pin to ground, a logic
Low. The switches typically exhibit about 2 ms of mechanical bounce and there is no active
debouncing circuitry, although such circuitry could easily be added to the FPGA design
programmed on the board. A 4.7K
Ω series resistor provides nominal input protection.
Push Button Switches
The Spartan-3 Starter Kit board has four momentary-contact push button switches,
indicated as
in Figure 1-2 . These push buttons are located along the lower edge of the
board, toward the right edge. The switches are labeled BTN3 through BTN0. Push button
switch BTN3 is the left-most switch, BTN0 the right-most switch. The push button
switches connect to an associated FPGA pin, as shown in
Table 4-2 . A detailed schematic
appears in Figure A-2 .
Pressing a push button generates a logic High on the associated FPGA pin. Again, there is
no active debouncing circuitry on the push button.
The left-most button, BTN3, is also the default User Reset pin. BTN3 electrically behaves
identically to the other push buttons. However, when applicable, BTN3 resets the provided
reference designs.
Table 4-1: Slider Switch Connections
Switch SW7 SW6 SW5 SW4 SW3 SW2 SW1 SW0
FPGA Pin K13 K14 J13 J14 H13 H14 G12 F12
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Table 4-2: Push Button Switch Connections
Push Button BTN3 (User Reset) BTN2 BTN1 BTN0
FPGA Pin L14 L13 M14 M13
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