Decoupling Functionality - 2023.2 English

Vivado Design Suite User Guide: Dynamic Function eXchange (UG909)

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2023.2 English

Because the reconfigurable logic is modified while the device is operating, the static logic connected to outputs of RMs must ignore data from RMs during dynamic reconfiguration. The RMs do not output valid data until reconfiguration is complete and the reconfigured logic is reset. There is no way to predict or simulate the functionality of the reconfiguring module.

You must decide how the decoupling strategy is solved. A common design practice to mitigate this issue is to register all output signals (on the static side of the interface) from the RM. An enable signal can be used to isolate the logic until it is completely reconfigured. Other approaches range from a simple 2-to-1 MUX on each output port, to higher level bus controller functions.

The static design should include the logic required for the data and interface management. It can implement mechanisms such as handshaking or disabling interfaces (which might be required for bus structures to avoid invalid transactions). It is also useful to consider the down-time performance effect of a DFX module (that is, the unavailability of any shared resources included in a DFX module during or after reconfiguration).

DFX Decoupler IP is available, which allows you to insert multiplexers to efficiently decouple AXI4-Lite, AXI4-Stream, and custom interfaces. More information about the DFX Decoupler IP is available on the website.