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Version: Vitis 2024.1
Embedded systems can be complex, that may contain multiple processors. You can also debug across software and hardware domains and can use PS-PL cross triggering. However, In this simple tutorial, you learn how we can debug over multiple processors using cross triggering.
Launch AMD Vitis™ Unified embedded tool in 2024.1 and create your platform. In this tutorial, you create two Hello World applications on different processors.
Note: Refer to the Getting Started Embedded tutorial for information on creating a new application.
While a system project is not a requirement for cross probing, it is useful to keep all the application components maintained in a system project. You can create a system project that has the two hello world applications. To create a system project, select File -> New Component -> System Project
Select your platform
Select your components
Additional Notes
You should place both applications into different sections in the DDR via the linker script or in different memories to avoid overlapping.
Set up the launch configurations, and scroll down to enable the Cross Triggering
Select Add Item under the Cross Triggering Breakpoints to setup the cross trigger signals. For example, here we want to trigger the cortex a53 #1 when there is a breakpoint on cortex a53 #0
Additional Notes
Refer to UG1400 for more information on the cross triggering signals
Additional Notes
The hello world print in a while loop for demo purposes is available here
You can then set a breakpoint on the first processor (on line 29 below)
Here, you can see that when the breakpoint hit on the first processor, it halted the second processor
Another very useful feature is the ability to debug between the hardware and software domains. To demonstrate this, I created a very simple hardware design in Vivado 2023.2 with an AXI GPIO and System ILA with Slot0 on the AXI Interface. I will enable the cross triggering between a System ILA in the PL that will cause a breakpoint on my processor.
I used the trivial hardware design below
Set up the launch configurations, and scroll down to enable the Cross Triggering
Setup the cross trigger signals by selecting Add Item under the Cross Triggering Breakpoints. For example, here we want to trigger the cortex a53 #0 when there is a trigger on the PS/PL interface.
Additional Notes
Users should refer to UG1400 For more information on the cross triggering signals
Users can click on the debug icon, and the device will configure and stop at the automatic breakpoint placed at &main. Users then need to setup the trigger in the ILA
Open the hardware manager and add the trigger condition. For example, here I added a trigger on the RDATA as shown below
Arm the trigger, and now return to Vitis Unified IDE, and resume. I have a while loop that will read the AXI GPIO
/* Set the direction for all signals as input */
XGpio_SetDataDirection(&Gpio, 1, 0xFFFFFFFF);
Xil_DCacheDisable();
while (1) {
Data = XGpio_DiscreteRead(&Gpio, 1);
}
I used the VIO to write to the DATA register of the AXI GPIO
This will cause the ILA to trigger, and this trigger will cause the processor (Cortex A53 #0) to suspend on a breakpoint
Alternatively, users can setup the cross triggering to trigger the System ILA when the processor is suspended. This is useful to validate a hardware functionality in the PL by stepping through a software application in Vitis Unified IDE and view the corresponding PL transaction.
For example, I used the same hardware design as above. However, I updated the software application to write to the AXI GPIO
/* Set the direction for all signals as output */
XGpio_SetDataDirection(&Gpio, 1, 0x0);
Xil_DCacheDisable();
while (1) {
XGpio_DiscreteRead(&Gpio, 1, 0x12345678);
}
The Cross Trigger configuration in the Launch Configuration can be seen below
Open the hardware manager and add the trigger condition. Here, I am just waiting on any Trigger.
Arm the trigger, and now return to Vitis Unified IDE, I have added a breakpoint at XGpio_DiscreteRead(). Once this is hit, the ILA will trigger.
Users can also Re-Arm the ILA and step through the code. This will trigger the ILA.
In the brief tutorial above, we explore the power debug feature available in the Vitis Unified IDE that allows users to cross probe across different processors and even across software and hardware domains.
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