Like AI Engine simulator, the hardware emulation flow can also dump VCD for AI Engine. To dump VCD, write AIE_DUMP_VCD=foo in a file and specify this file for the -aie-sim-options option of launch_hw_emu.sh.
It is usually helpful to view the input and output of AI Engine in the waveform. The -g option can be added to launch_hw_emu.sh to launch the XSIM waveform. The command looks like the following:
```
./launch_hw_emu.sh -g -aie-sim-options ./sim_options.txt
```
When the XSIM GUI pops up, add ai_engine_0 or the PL kernels’ signals to the waveform. Click Start in XSIM. In the Linux prompt, run the following command:
```
cd /run/media/mmcblk0p1
./host.exe a.xclbin
```
After the PS code completes in Linux, check the input to the AI Engine S00_AXIS and the output from the AI Engine M00_AXIS:
After the PS receives 104 samples, the design hangs. TVALID is always High, indicating that the PL kernel mm2s is still trying to send data to the AI Engine, but TREADY from the AI Engine turns to Low, and remains Low. There are also no samples from the AI Engine to the PL in the M00_AXIS interface of the AI Engine.
Analysis of the VDC file in Vitis Analyzer is similar to analysis in AI Engine simulator. A workaround is to move the VCD file generated by the hardware emulation flow to the working directory and open it:
```
vitis_analyzer aiesimulator_output/default.aierun_summary
```