Tandem Configuration is a staged configuration that brings up the PCIe protocol less than 100 ms after power to Versal adaptive SoC is stable. A stage 1 programmable device image (PDI) achieves this. The user application downloads the rest of the device, including the PL, as a stage 2 PDI.
In Versal adaptive SoC, Tandem Configuration uses the CPM integrated block. Tandem Configuration supports the Tandem PCIe and Tandem PROM modes. For more information, refer to the Versal Adaptive SoC CPM DMA and Bridge Mode for PCI Express Product Guide (PG347).
Vivado automatically enables Tandem formatting with Segmented Configuration, but only when the CPM is in endpoint mode for specific devices. Support is in place for Versal Premium Series and Versal HBM Series devices with CPM5 blocks. Also, support applies to Versal AI Edge Series Gen 2 and Versal Prime Series Gen 2 for MDB5 blocks.
When you select Segmented Configuration and one or both controllers are set as endpoints, the system builds the boot PDI in a Tandem fashion. This ensures the system meets the 100 ms goal. You can deliver the PLD PDI over the PCIe link to complete the device configuration, instead of a Tandem stage 2 PDI.