Networked Multiport Interface - 2021.1 English

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

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2021.1 English

Dynamic Function eXchange optimizes traditional FPGA applications by reducing size, weight, power, and cost. Time-independent functions can be identified, isolated, and implemented as reconfigurable modules (RM) and swapped in and out of a single device as needed. A typical example is a 40G OTN muxponder application. The ports of the client side of the muxponder can support multiple interface protocols. However, it is not possible for the system to predict which protocol will be used before the FPGA is configured. To ensure that the FPGA does not have to be reconfigured and thus disable all ports, every possible interface protocol is implemented for every port, as illustrated in Networked Multiport Interface.

Figure 1. Network Switch Without Partial Reconfiguration

This is an inefficient design because only one of the standards for each port is in use at any point in time. Dynamic Function eXchange enables a more efficient design by making each of the port interfaces an RM, as shown in Networked Multiport Interface. This also eliminates the MUX elements required to connect multiple protocol engines to one port.

Figure 2. Network Switch With Partial Reconfiguration

A wide variety of designs can benefit from this basic premise. Software defined radio (SDR), for example, is one of many applications that has mutually exclusive functionality, and which sees a dramatic improvement in flexibility and resource usage when this functionality is multiplexed.

There are additional advantages with a dynamically reconfigurable design other than efficiency. In the Networked Multiport Interface example, a new protocol can be supported at any time without affecting the static logic, the switch fabric in this example. When a new standard is loaded for any port, the other existing ports are not affected in any way. Additional standards can be created and added to the configuration memory library without requiring a complete redesign. This allows greater flexibility and reliability with less down time for the switch fabric and the ports. A debug module could be created so that if a port was experiencing errors, an unused port could be loaded with analysis/correction logic to handle the problem real-time.

In the Networked Multiport Interface example, a unique partial BIT file must be generated for each unique physical location that could be targeted by each protocol. Partial BIT files are associated with an explicit region on the device. In this example, sixteen unique partial BIT files to accommodate four protocols for four locations.