FIFO Depth Constraints - 2022.1 English

Versal ACAP AI Engine Programming Environment User Guide (UG1076)

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2022.1 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)}