Digilent Pegasus Board User Manual
Digilent Hardware
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w w w . d i g i l e n t i n c . c o m ™
Revision: August 11, 2005
215 E Main Suite D | Pullman, WA 99163
(509) 334 6306 Voice and Fax
Copyright Digilent, Inc. All rights reserved
12 pages
Doc: 500-223
Overview
The Pegasus circuit board provides a complete
circuit development platform centered on a
Xilinx Spartan 2 FPGA. Pegasus features
include:
•
a 50K-gate Xilinx Spartan 2 FPGA with
50K gates and 200MHz operation (a
200K-gate version is also available)
•
a XCF01S Xilinx Platform Flash ROM
(XCF02S for 200K gate version)
•
a collection of I/O devices including eight
LEDs, four-digit seven-segment display,
four pushbuttons, and eight slide
switches
•
a 50MHz oscillator and a socket for a
second oscillator
•
PS/2 and VGA ports
•
96 I/O signals routed to three standard
40-pin expansion connectors
•
all I/O signals have ESD and short-circuit
protection
•
a JTAG programming port.
The Pegasus board has been designed to
work seamlessly with all versions of the Xilinx
ISE CAD tools, including the free WebPack
tools available from Xilinx. A growing collection
of low-cost expansion boards can be used with
the Pegasus board to add analog and digital
I/O capabilities, as well as various data ports
like Ethernet and USB. The Pegasus board
ships with a power supply and programming
cable, so designs can be implemented
immediately without the need for any additional
hardware.
Important: This reference manual is
updated for Rev. D Pegasus Boards with a
5V power supply. For a manual for a
previous Pegasus board using a 3.3V
power supply, e-mail
Functional Description
The Pegasus board provides an inexpensive,
robust, and easy-to-use platform that anyone
can use to gain experience with FPGA devices
and modern design methods. The Pegasus
board is centered on the Spartan 2 FPGA, and
it contains all needed support circuits so
designs can get up and running quickly. The
large collection of on-board I/O devices allows
many designs to be completed without the
need for any other components. Three
standard expansion connectors allow designs
to grow beyond the Pegasus board, either with
user-designed boards or any one of several
analog and digital I/O boards offered by
Digilent. Each expansion connector provides
system voltages and 32 unique I/O signals,
with all I/O signals protected against damage
from ESD and short-circuit connections. JTAG
signals are routed to two expansion
connectors, allowing peripheral boards to drive
the scan chain or to be configured along with
the Spartan FPGA. The collection of on-board
I/O devices and signal protection networks
make the Pegasus board ideally suited to
educational settings.
A1
Xilinx Spartan2 XC2S50-PQ208
Clock
(50MHz)
Power
jack
5-9VDC
2.5VDC
regulator
Config
ROM
3.3VDC
regulator
J
T
A
G
8 switches
4 buttons
8 LEDs
4 7-seg.
displays
PS2
Port
VGA
Port
A2
B1
Expansion Connectors
Figure 1. Pegasus circuit board block diagram