Digilent Basys Board Rev.C 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 8, 2006
215 E Main Suite D | Pullman, WA 99163
(509) 334 6306 Voice and Fax
Copyright Digilent, Inc. All rights reserved
12 pages
Doc: 502-107
Overview
Digilent’s Basys circuit board is an integrated
circuit development platform based on a Xilinx
Spartan 3E Field Programmable Gate Array
(FPGA). The Basys board provides a low-
cost, introductory development platform for
engineers to try new designs or learn about
FPGAs and modern CAD tools. Basys
features include:
• 100,000 gate Xilinx Spartan 3E FPGA;
• JTAG programming port;
• XCF02S Xilinx Platform Flash ROM to
store FPGA configurations;
• Large collection of I/O devices including
eight LEDs, four-digit seven-segment
display, four pushbuttons, and eight slide
switches;
• PS/2 and VGA ports;
• User-selectable
oscillator
(25/50/100MHz), plus a socket for a
second oscillator;
• Four 6-pin header ports for user I/O and
peripheral module connection;
• ESD and short-circuit protection on all I/O
signals.
Functional Description
The Basys board provides an inexpensive,
robust, and easy-to-use platform that anyone
can use to gain experience with FPGA devices
and modern design methods. It is centered on
the Spartan 3E 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 allow many designs to be completed without the
need for any other hardware, making the Basys an ideal introductory platform for experimenting with
new designs or learning about FPGAs and CAD tools. The four standard 6-pin expansion connectors
allow designs to grow beyond the Basys board, either with user-designed boards or breadboards
and/or peripheral module (Pmod) boards offered by Digilent. (Pmods are inexpensive analog and
digital I/O modules that offer A/D conversion, D/A conversion, motor drive, sensor input, and a host of
other features). Signals on each 6-pin expansion connector are protected against damage from ESD
and short-circuit connections, ensuring a long operating life in any environment. The Basys board
works seamlessly with all versions of the Xilinx ISE tools, including the free WebPack tools. It ships
with a power supply and programming cable, so designs can be implemented immediately without the
need for any additional hardware.
JA
Clock
(100,
50, or
25
MHz)
Power
jack
5-12VDC
Platform
Flash
(config
ROM)
3.3VDC
regulator
JTA
G
8 switches
4 buttons
8 LEDs
4 7-seg.
displays
PS2
Port
JB
JC
6-pin connectors
For A/D & D/A converters,
motor drivers, etc.
2.5VDC
regulator
1.2VDC
regulator
JD
4
4
4
4
Xilinx Spartan3E-100 TQ100
Featuring 4 18-bit multipliers and 9Kbytes of Block RAM
VGA Port
Figure 1:
Basys block diagram
Document Outline
- Overview
- Functional Description
- Power Supply
- User I/O
- Mouse
- The mouse outputs a clock and data signal when it is moved; otherwise, these signals remain at logic ‘1’. Each time the mouse is moved, three 11-bit words are sent from the mouse to the host device. Each of the 11-bit words contains a ‘0’ start bit, followed by 8 bits of data (LSB first), followed by an odd parity bit, and terminated with a ‘1’ stop bit. Thus, each data transmission contains 33 bits, where bits 0, 11, and 22 are ‘0’ start bits, and bits 11, 21, and 33 are ‘1’ stop bits. The three 8-bit data fields contain movement data as shown below. Data is valid at the falling edge of the clock, and the clock period is 20 to 30KHz.