PL to AI Engine - PL to AI Engine - 2026.1 English - XD100

After bootup and device configuration, the application can begin to run. In this design, there is a PL kernel called random noise that is generating data that is going directly into the AI Engine. The key here is looking at the s_axi_control interface to find out when the PS sends the run signal.

1. To view the specific signals controlling the PL kernel, run the following command.

   source ../../../../tcl/pl_to_aie.tcl
   

2. Expand the CIPS group down to the Row 0. Zoom into a specific region. In the following screenshot, the red area is the zoom region.

   

   After the zoom in, something similar to the following displays.

   

   Here, notice that the PS is using the Full Power Domain (FPD) interface to send the AXI signal to turn on. Notice that there are two blocks shown. This is the PS telling the random_noise and s2mm kernels to start running.

   If you zoom in more, you can view more specifics of the transactions.

   

   Notice that the s_axi_control has a read transaction slightly after the second transaction has started of the FPD interface.

3. Expand the vitis_design_CIPS_0_0_M_AXI_FPD_tlm interface and the Outstanding Reads, and you see a Row 0. If you move the mouse over the #3 or #4, a context help menu shows you some signal information on where data is transferring. Notice the ARADDR value of 0xa4060000 for #3 and 0xa4050000 for #4, and understand that this is the address to the PL kernels that the Vitis linker autoassigns it during linking. From the host code, you can determine that these kernels are activated before the AI Engine, soon after the application starts, so it is safe to assume these signals start them. Remember that these kernels are simpler than others—more complex kernels result in different transactions.

4. Zoom to fit by clicking the Zoom Fit button (). Expand the NOISE group and expand Out_r.

   

5. Notice the large green line after the random_noise kernel starts. This is a series of many transactions of the PL kernel transferring data to the AI Engine. There are a few red sections in the waveform. This is a link stall, or where the kernel has stalled and is caused by the AI Engine.

6. Zoom to fit by clicking the Zoom Fit button.