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 rest of the device, including the PL, can be downloaded by the user application as a stage 2 PDI.
In Versal adaptive SoC, Tandem Configuration is accomplished using the CPM integrated block. Tandem Configuration supports the Tandem PCIe and Tandem PROM modes. For more information, see the Versal Adaptive SoC CPM DMA and Bridge Mode for PCI Express Product Guide (PG347).
Vivado 2025.1 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. When Segmented Configuration is selected and one or both controllers are set as endpoints, the boot PDI is constructed in a Tandem fashion to ensure the 100 ms goal is achieved. The PLD PDI (instead of a Tandem stage 2 PDI) can be delivered over the PCIe link to complete the device configuration. Support for devices with CPM4 resources is planned for a future release.