Viewing the Generated VCD in the Vitis Unified IDE - 2025.2 English - UG1076

The Vitis Unified IDE displays the signals generated in the VCD. By default, the VCD generates stream switch FIFO signals, and signals connected between the PLIO and the AI Engine. The IDE displays these signals. The following section explains the details of the VCD signal selection.

AI Engine I/O

When you enable the AIE_DUMP_VCD_IO option in the options.txt file, the IDE displays I/Os for each kernel. You can also see all stall signals for lock requests.

Figure 1. AI Engine VCD I/O Data Display

DMA

When you enable the AIE_DUMP_VCD_DMA in the options.txt file, the IDE displays the DMA transaction on the buffers. The IDE also displays the following:

• DMA transactions.
• MM2S, and S2MM transactions with their channel IDs.
• Buffer descriptors (BD0,BD1).
• The associated locks (lock0, lock1). Includes the values on the locks which indicate if the locks are acquired for read or write.

Figure 2. DMA VCD Data Display

Core

When you enable the AIE_DUMP_VCD_CORE option in the options.txt file, the core signals display. This is a combination of kernels, I/O and DMA signals. Also displayed are the following items:

• All functions and their transitions.
• All the stalls on the functions.
• The kernel I/O with the core requesting read and write locks.
• DMA transactions.
• MM2S, and S2MM transactions with their channel IDs.
• Buffer descriptors.
• The associated locks. Includes the values on the locks which indicate if the locks are acquired for read or write.

Figure 3. Core Data Display

AI Engine Interface Tile (Shim)

When you enable the AIE_DUMP_VCD_SHIM option in the options.txt file, the AI Engine interface tile signals display. Also displayed are the following items:

• The streams to and from the tiles.
• Net mapped to the tile.
• Nets that pass through the tiles if the stream switch option is enabled along with the tile option.

Figure 4. AI Engine Interface Tile Data Display

Stream Switch

When you enable the AIE_DUMP_VCD_STREAM_SWITCH option in the options.txt file, the system shows the stream switch signals. The Trace contains all the nets related to the network for all the tiles under the stream switch. The trace only displays network events.

Figure 5. Stream Switch Data Display