Nexys 3™ FPGA Board Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
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(EDK is used for MicroBlaze™ embedded processor-based designs). Digilent's Adept software or Xilinx's iMPACT
software can be used to program the FPGA or ROMs using the Adept USB port.
During JTAG programming, a .bit or .svf file is transferred from the PC to the FPGA using the Adept USB port. When
programming a non-volatile PCM device, a .bit, .bin, or .mcs file is transferred to the in a two-step process. First,
the FPGA is programmed with a circuit that can program PCM devices, and then data is transferred to the PCM
device via the FPGA circuit (this complexity is hidden from the user – a simple "program ROM" interface is
presented by the programming software. Note the PCM devices are next-generation Flash ROM devices, and they
are often referred to as "Flash" or "ROM" memory). After the PCM device has been programmed, it can
automatically configure the FPGA at a subsequent power-on or reset event as determined by the J8 jumper
setting. Programming files stored in the PCM devices will remain until they are overwritten, regardless of power-
cycle events.
The FPGA can be programmed from a memory stick attached to the USB-HID port if the stick contains a single .bit
configuration file in the root directory, the J8 Programming Mode jumper is set to JTAG (both jumpers loaded), and
board power is cycled. The FPGA will automatically reject any .bit files that are not built for the proper FPGA.
After being successfully programmed, the FPGA will cause the "Done" LED to illuminate. Pressing the Reset button
at any time will reset the configuration memory in the FPGA. After being reset, the FPGA will immediately attempt
to reprogram itself from one of the PCM devices if the J8 Mode jumper is set to BPI or SPI mode.
Adept
USB Port
Power
Switch
USB HID
Host Port
Power
Jack
JTAG
Header
MODE
Jumper
Power
Good LED
Done
LED
Reset
Button
Power Select
Jumper
LEDs
Slide switches
Push buttons
7-seg
Display
USB
UART
VGA
Port
10/100
Ethernet
Pmod
Connectors
VHDC
Conncector
