Digital Signal Processing Reference
In-Depth Information
For this tutorial, you will add three PIO components: one for the pushbuttons,
one for the switches, and one for the LEDs. First, add a PIO component for the
pushbuttons to your processor design by expanding
Peripherals
Microcontroller Peripherals
. Select
PIO (Parallel I/O)
and click
Add…
.
When the PIO configuration dialog box appears, set the
Width
of the interface
to
4
bits (there are four pushbuttons) and set the
Direction
to
Input ports only
as shown in Figure 17.9(a). Click
Next
to continue. On the next configuration
page, set the options as shown in Figure 17.9(b). Click
Finish
to add the
component. In the SOPC Builder, rename the PIO module to
buttons
.
Using the same procedure as above, add a second PIO component for the
dipswitches. The settings for the PIO devices are shown in Figure 17.10.
Rename this PIO module to
switches
.
Figure 17.10
These are the settings for the switch PIO device to be added to the Nios II system.
Finally, add a third PIO component for the LEDs. On the first configuration
page, set
8
bits for the
Width
, and set the
Direction
to
Output ports only
.
When the PIO is an output-only device, the interrupt and edge-capture options
are not applicable. Rename this PIO module to
leds
.
17.8 Adding an SRAM Memory Controller
Add the SRAM memory controller to your Nios II processor by expanding
University Program DE2 Board
. (The SRAM components are identical for
the DE1 and DE2 boards, so the SRAM component may be added from either
library.) Select
SRAM
and click
Add…
. When the SRAM configuration dialog
box appears, click
Finish
to add the component. This component does not have
