Digilent 410-155P-KIT User Manual
Page 3
Basys2 Reference Manual
Digilent
www.digilentinc.com
To program the Basys2 board, set the mode
jumper to PC and attach the USB cable to
the board. Start the Adept software, and
wait for the FPGA and the Platform Flash
ROM to be recognized. Use the browse
function to associate the desired .bit file with
the FPGA, and/or the desired .mcs file with
the Platform Flash ROM. Right-click on the
device to be programmed, and select the
“program” function. The configuration file
will be sent to the FPGA or Platform Flash,
and the software will indicate whether
programming was successful. The “Status
LED” LED (LD_8) will also blink after the
FPGA has been successfully configured.
For further information on using Adept,
please see the Adept documentation
available at the Digilent website.
Oscillators
The Basys2 board includes a primary, user-settable silicon oscillator that produces 25MHz, 50MHz, or
100MHz based on the position of the clock select jumper at JP4. Initially, this jumper is not loaded
and must be soldered in place. A socket for a second oscillator is provided at IC6 (the IC6 socket can
accommodate any 3.3V CMOS oscillator in a half-size DIP package).
The primary and secondary
oscillators are connected to global clock input
pins at pin B8 and pin M6 respectively.
Both clock inputs can drive the clock synthesizer
DLL on the Spartan 3E, allowing for a wide range
if internal frequencies, from 4 times the input
frequency to any integer divisor of the input
frequency.
The primary silicon oscillator is flexible and
inexpensive, but it lacks the frequency stability of
a crystal oscillator. Some circuits that drive a
VGA monitor may realize a slight improvement in
image stability by using a crystal oscillator
installed in the IC6 socket. For these applications,
a 25MHz (or 50MHz) crystal oscillator, available
from any catalog distributor, is recommended
(see for example part number SG-8002JF-PCC at
).
Spartan-3E
FPGA
B8
CLK_OUT
Linear Tech.
LTC6905
Oscillator
Frequency
Select
Jumper
25MHz
50MHz
100MHz
Figure 5. Basys2 oscillator circuits
XCF02
Platform
Flash
JTAG
Spartan 3E
FPGA
Mode
Jumper
PC ROM
USB miniB
connector
Atmel
AT90USB2
Slave
serial
port
JTAG
port
LD8
Figure 4. Basys2 Programming Circuits
Doc: 502-138
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