FIFO Depth Constraints - 2021.2 English

Versal ACAP AI Engine Programming Environment User Guide (UG1076)

Document ID
English (United States)
Release Date
2021.2 English

There are limited switch and DMA FIFOs on the device. When deciding on fifo_depth constraints it is important to consider the amount of FIFOs you specify for an area. This includes taking into account if the nets that have fifo_depth constraints also have area group constraints. In this case make sure that all fifo_depth constraints can be met within the specified area.

If there is a high contention for switch FIFOs, consider moving to DMA FIFOs. Without changing the fifo_depth you can specify the DMA FIFO type using the following constraint.

location<fifo>(net1) = { dma_fifo()}

With careful consideration FIFO locations constraints can be applied, as shown in the following example.

location<fifo>(net2) = { dma_fifo(aie_tile, 15, 0, 0x3100, 32) };
location<fifo>(net3) = { ss_fifo(shim_tile, 16, 0, 0), dma_fifo(aie_tile, 17, 0, 0x3100, 48)}