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2.
The board will come alive and you will see little green LEDs glowing on it. After a few seconds you will see LED DC17
start flashing if the board already has a configuration file setup on it. This means the NPX microcontroller is configuring the
FPGA. Once the configuration is done you will see DC17 stop flashing and change to solid green. This means the FPGA is
configured and running its program.
3.
Once the Mark 1 is connected to your computer Windows will try to install the appropriate device driver. This should
succeed without any issues. When it does, you will see a new Removable Disk in Windows Explorer as shown in Figure 3.
Figure 3 – New Device Appears in Windows Explorer
4.
On the removable disk you will see pre-compiled programs that come saved on the Mark 1’s non-volatile memory.
Figure 4 – Files Factory Preloaded Onto the Mark 1 Board as Shown in Windows Explorer
5.
The file “config.bit” is the file the NPX microcontroller is looking for to load onto the FPGA at boot time.
“Config.bit.original” is a backup of the demo program shipped with the Mark 1.
6.
To make the system load a totally different FPGA configuration on boot up, simply delete the “config.bit” file and replace it
with a .bit file of your choosing. Just make sure the file that is used for a replacement is named “config.bit.” It’s as simple as
that. No special programmer hardware needed. Later in this guide we will show you how to make the Xilinx ISE generate a
.bit file from your custom design.
7.
But, for demonstration purposes let’s have the FPGA run a more interesting program. After deleting the “config.bit” file that
is shipped with the board, use Windows Explorer to make a new copy of “led_counter_i2c_buffered.bit.” If you’re using
Windows 7, highlighting the file and doing a Copy, Paste will generate a copy of the file called “led_counter_i2c_buffered -
Copy.bit.” Make a copy of the file before renaming it in the interest of preserving this example design for later use.
8.
Now rename “led_counter_i2c_buffered - Copy.bit.” to “config.bit.”
9.
The final step is to reset the board – just push button PB5.
On system reset you will see the NPX microcontroller start configuring the FPGA with the config.bit file you just chose. Once it’s
done configuring, you will immediately see LEDs 0 through 7 on the edge of the board start dancing wildly. Each LED represents a
bit
. Because there are 8 LEDs total these LEDs can display 256 unique combinations. What they are actually doing is a very rapid
binary counting
sequence from 0 to 255 in about three seconds. When the sequence finishes it just starts over. Note that the
least
significant bit
is LED 0 and the
most significant bit
is LED 7.
This demo is a very simple example of what’s possible on this FPGA platform. With a little more learning and
HDL
code
development, you can be on your way to blinking lights in your own sequence in no time! …Or reading MP3s off your SATA
connected, terabyte hard drive while playing the audio and displaying a visualizer! …For example.
4.
Developing Your Own Design
Now that you have a bit of FPGA background we will move on to the hands-on part of this instruction. In the following sections you
will learn what is required to actually design and build your own FPGA configuration and then run it on the hardware. The example
design given below is rather simple, but seeing the major FPGA software development concepts and workflows that are exposed
through this tutorial will be instrumental in understanding the big picture.