A FreeRTOS BSP for the Xilinx SDK
The Xilinx Software Development Kit (SDK)
can automatically generate a board support package from a hardware definition file.
The board support package provides comprehensive run time, processor and peripheral
support. It is also possible for the BSP to include the FreeRTOS real time
Including FreeRTOS in the BSP presents the application writer
with a pre-configured FreeRTOS environment that does not require
any source files to be added manually, any callback functions to be provided by
the application code, and allows FreeRTOSConfig.h to be edited within the IDE.
Instructions for creating a FreeRTOS BSP are provided below. The FreeRTOS
download also includes separate and comprehensive demo applications for the
Xilinx Zynq dual core ARM Cortex-A9 processor,
an ARM Cortex-A53 core on
the UltraScale+ MPSoC (64-bit), an
ARM Cortex-R5 core
on the the UltraScale+ MPSoC (32-bit), and
soft-core processors. Those comprehensive demo applications, as provided in the
the FreeRTOS download, use a standalone BSP. A standalone BSP does not itself
include FreeRTOS, so FreeRTOS is instead built as part of the application. It
is still important to read the documentation pages for those standalone demos,
even when a FreeRTOS BSP is being used, as the pages provide information
on how to use FreeRTOS on those ARM and Xilinx architectures.
Creating a Hello World Project That Uses the FreeRTOS BSP
The board support package (BSP) repositories that ship as part of the Xilinx SDK
come with a simple FreeRTOS hello world application. The hello world project is
created as follows:
Select “New: Application Project” from the SDK’s “File” menu to bring up
the new project Window, then give the project a name.
The “New: Application Project” menu option
In the new project window – first select the hardware platform in use.
Pre-defined hardware platforms are provided for all the processors supported
by FreeRTOS (Zynq ARM Cortex-A9, UltraScale+ ARM Cortex-A53 and ARM Cortex-A9
cores, and Microblaze). The image below shows the pre-configured ZC702
platform being used.
After the hardware platform has been selected, select the processor. The
image below shows the ps7_cortexa9_0 processor selected.
After the processor has been selected, select the OS Platform. The
image below shows freertos822 selected.
Defining the project settings
Click the “Next” button to move onto the next stage. The Templates
Window will appear – select the “FreeRTOS Hello World” template, then
click the “Finish” button to generate both the FreeRTOS BSP and the
Hello World project.
Selecting the FreeRTOS Hello World template
Editing the FreeRTOS Configuration
A FreeRTOSConfig.h file was automatically created when the FreeRTOS BSP was
generated. The values contained in the file can be viewed, and edited, using the following
Select “Board Support Package Settings” from the “Xilinx Tools” menu
in the SDK. The Board Support Package Settings window will appear.
Select FreeRTOS in the left pane of the Board Support Package Settings
window. The table in the right pane will populate with the FreeRTOSConfig.h
Edit the settings as necessary, then click the “Ok” button to update
FreeRTOSConfig.h with the edited values, and re-build the BSP.
The Board Support Package Settings window
Starting a Debug Session
It is therefore necessary to ensure the SDK launch configurations used to start
a debug session resets the entire CPU, and runs the necessary initialisation
scripts. A debug configuration suitable for running the Zynq
demo is shown in the image below.
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