Tech Briefs

Use of FPGAs eliminates cables when connecting DSPs.

A method for networking, and a network of, digital signal processors (DSP) via at least one field-programmable gate array (FPGA) enables the simultaneous broadcast of data from a DSP to a number of DSPs. The apparatus comprises a host DSP, at least one FPGA in communication with the host DSP for receiving a digital signal from the host DSP, and at least one non-host DSP in communication with at least one FPGA for receiving the digital signal.

The number of non-host DSPs receiving data broadcast from the host DSP may be greater than the number of communication ports located on the host DSP. The networking method does not require each non-host DSP to be physically connected to the host DSP. This is achieved by interposing an FPGA between the host DSP and the non-host DSPs. The FPGA serves to receive the broadcast data from the host DSP, to buffer the data received, and to handle the communication and dissemination of the buffered broadcast data to multiple non-host DSPs.

The host DSP is housed within a host computer, preferably a PC. The host DSP is in communication with the FPGA via a connection that connects a communication port located on the host DSP to a communication port located on the FPGA. Connection provides bidirectional communication between the host DSP and the FPGA. The FPGA has multiple additional communication ports, which are utilized to communicate with a multitude of additional non-host DSPs. The FPGA communicates with each non-host DSP via a connection that connects a single communication port located on the FPGA to a single communication port located on a non-host DSP. In this manner, bidirectional communication is enabled between each non-host DSP and the FPGA.

In operation, the host DSP communicates a single stream of data to the FPGA via a connection. It is a property of FPGAs that they may be dynamically programmed to execute software instructions. The FPGA is therefore programmed to buffer the stream of data received by the host DSP and to transmit the received and buffered data out via the plurality of communication ports in communication with non-host DSPs. In addition to transmitting the buffered data, the FPGA is preferably programmed to perform any and all initialization and data synchronization activities required to facilitate the communication of buffered data between the FPGA and all non-host DSPs. Such communication may be either synchronous or asynchronous.

The FPGA is constructed to comprise an internal memory capable of storing, retrieving, and returning upon request, digital data. The FPGA may be in communication with an external storage device wherein the data broadcast by the host DSP to the FPGA may be buffered and stored in external storage device, and retrieved by the FPGA as required for broadcast to the non-host DSPs.

In addition to communicating with non-host DSPs, the FPGA may similarly communicate with a peripheral device via a communication port located on the FPGA and connected to the peripheral device.

This work was done by C. Ray Dutton of the Naval Undersea Warfare Center.

NUWC-0003

This Brief includes a Technical Support Package (TSP).

FPGA-Based Communication Channel for Digital Signal Processor Chips (reference NUWC-0003) is currently available for download from the TSP library.

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