Digital Signal Processing Reference
In-Depth Information
17.12 Adding Components to the External Bus
Once the Avalon tri-state bridge has been added, the peripherals that are going
to connect to the external peripheral bus can be added. First, add the Flash
memory controller by expanding
Memories and Memory
Controllers
Flash
. Select
Flash Memory (CFI)
and click
Add…
. When the
Flash memory configuration dialog box appears, set the options as shown in
Figure 17.13. In the SOPC Builder, rename the flash module to
flash
.
(a)
(b)
Figure 17.13
These are the Flash memory settings for use with the Flash on the DE boards.
17.13 Global Processor Settings
All of the necessary peripherals have been added now. The next step is to
configure some global settings for your processor.
To view and modify the bus connections in your processor, select
View
Show
Connections Column
. (If
Show Connections Column
is already selected, then
un-select it and select it again.) This will expand the
cpu
and
ext_bus
modules
in the table of peripherals and show the bus connections. The three buses are
displayed vertically. From left-to-right, the buses are the main system
instruction, main system data, and tri-state data bus. Notice that the UARTs,
timer, LCD, and PIO components are only attached to the system data bus since
they don't normally interact with instruction memory. SRAM, SDRAM, and the
Avalon Tristate Bridge are connected to both the system instruction and system
data buses, because the memory devices can store both data and instruction
memory. Finally, the Flash memory device is unconnected. It must be manually
connected to the appropriate tristate bus. Hover your mouse over the
connections column just to the left of the
flash
module. An open circle will
appear on the tri-state data bus. Click on the open circle to connect the
flash
module to the external tristate bus (a connection is denoted by a solid, filled-in
circle). The final SOPC Builder window should look like the screen shot in
Figure 17.14.
