Skip to content

Designing an FPGA Processor With Reconfigurable Logic

Designing an FPGA processor with reconfigurable logic involves two distinct approaches: schematic design and hardware description language (HDL). HDL is more suitable for large structures and provides high-level functional behavior, while schematic entry makes the design appear more quickly. This article will discuss both approaches and explain their respective benefits. Ultimately, the goal is to simplify the design process by enabling the most efficient implementation of reconfigurable logic for a given application.

Partial reconfiguration

Partial reconfiguration of an FPGA processor using reconfigurable logic allows users to set different parameters for the FPGA processing unit. This feature avoids energy waste due to redundant information. However, this technique requires careful analysis to ensure that the energy savings do not outweigh the additional computation needed. In addition, the process requires Xilinx iMPACT software and a JTAG chain.

Conveniently, this technology enables Rayming PCB & Assembly to change the functionality of a certain module or entire module without disrupting the rest of the device. The partial reconfiguration also allows developers to reuse and port their hardware for various applications. By reprogramming only, a part of a device, developers can minimize the overall cost and power of the system. Partial reconfiguration of an FPGA processor with reconfigurable logic allows developers to change only a specific portion of a device,

An external controller loads a new design onto the FPGA in partial reconfiguration. This feature is helpful for devices that need to reconfigure portions of their processor but need to retain other functionality. The design can be valuable multiple times, and we can configure the FPGA multiple times. This process is also helpful for communication devices. This method also allows designers to control multiple connections and encryption while preserving the space for more designs.

There are several studies on the partial reconfiguration of FPGAs. In one study, Papadimitriou et al. surveyed the performance of several commercially available architectures using programmable logic. They concluded that the PR process was feasible. Moreover, partial reconfiguration of FPGAs reduces idleness and underutilization of resources. Some limitations come with partial reconfiguration, but the advantages outweigh the limitations.

On-chip cache memory

On-chip cache memory is helpful in FPGA processors with reconfigurable logic to reduce reconfiguration time and implement less logic. This method uses the same die area like a bank of SRAM. However, fast context switching results in higher power dissipation. In such applications, on-chip cache memory is a superior alternative. This type of architecture is particularly well-suited for computing applications.

An FPGA processor with reconfigurable logic has large on-chip data and instruction caches to store thousands of instructions. As a result, high-bandwidth instruction distribution is necessary. One instruction tells an array cell what function it should perform and how to route its inputs and outputs. Changing the active set of array instructions can take hundreds or thousands of compute cycles. But an OPGA processor can perform multiple tasks at the same time.

An FPGA processor with reconfigurable logic has a fast interface to external memory. However, when power is lost, it loses its program and must be reprogrammed. OPGAs use a fast interface with memory to reprogram the chip in real-time to minimize reconfiguration time. Another solution implemented by Xilinx is on-chip cache memory. Cache memory stores frequently used configuration templates, reducing the number of times the processor accesses external memory.

On-chip cache memory can be helpful for a wide variety of applications. For example, it is beneficial in image processing applications, where the image is analyzed. An FPGA processor with reconfigurable logic can deal with complex input images. It can adapt to changes in orientation and illumination. And it can be time-multiplexed for different tasks on the same input image. It can also implement learning.

On-chip photodetectors

Using on-chip photodetectors in an FPL process is a promising new way to implement image processing in a high-speed digital computer. The size of an on-chip photodetector (ORD) is a function of the pixel size, and the cost of the corresponding CLBs is a good indication of this. As with all hardware devices, the number of CLBs depends on the overall size of the chip.

A single OPGA chip contains several CLBs optically programmed by 16×2 photodetectors. In addition to being compact and light-efficient, they also feature an array of photodetectors arranged in a sparse overlay. Both topologies provide several advantages, such as a reduced area overhead and reduced integration time.

In addition to their flexibility, TBUs can operate as optical switches, directional couplers, or optical switches. Furthermore, TBUs can be helpful as a spare component to implement self-healing photonic integrated circuits. However, thermal stability is a critical requirement. As a result, thermal stabilization and thermal management are essential for reliable chip operation.

We can perform reconfigurability of the chip by employing fast interfaces to the memory. One solution to this problem is using a DMA-powered reconfiguration engine known as PCAP. As a result, it takes less time to load a full bitstream than a partial one, which is the case for reconfigurable FPGAs. In addition, this approach is more efficient because each reconfigurable region is mapped on a single chip rather than requiring separate memory for each configuration.

On-chip serializers

Reconfigurable logic can be helpful in several applications. For example, it can provide byte reordering for attached peripherals, buffer data for free bus cycles, and store profiling data. Processors may also be necessary to extract data from various file formats and rearrange them for storage. In other cases, it may be helpful to store or process trace data.

A reconfigurable control and programmable i/o unit can be combined. In this way, the reconfigurable units can share space and be average in performance. A simple reconfigurable control can borrow space from a large reconfigurable unit. The reconfigurable logic block includes hooks to processor control logic. It can also be helpful as a PFU or a reconfigurable i/o. The reconfigurable logic block can also include behavior modifications that allow it to be tuned for a particular application or adapted to provide a specific semantic.

Another type of FPGA processor with reconfigurable logic also has analog capabilities. It features programmable slew rates on output pins, enabling users to set low slew rates on lightly-loaded inputs or high-speed channels. In addition to this, it includes voltage-controlled oscillators and phase-locked loops for clock generation.

Time-multiplexing

Reconfigurable processors allow users to customize the processing of a given class of objects. They can adapt to changes in the illumination and orientation of an input object. They can implement learning. This allows users to customize the processing of a specific application based on various input characteristics.

The core of the processor is a Virtex-4 FPGA from Xilinx Inc. This chip has a USB interface for interfacing with the microchips of receiving boards. It also has a serial programming interface link that controls the chip’s characteristics.

Overlays can also benefit from time multiplexing. Unlike traditional hardware design, time multiplexing allows for behavior changes while the compute kernel is still running. However, time multiplexing can lead to significant area overhead due to storage requirements for instructions. Several factors contribute to this problem. For example, some overlays are architecture-based, while others are not. And many of them operate at a slow frequency.

A fast interface with memory can reduce the time of reconfiguration. An OPGA uses this method and can reprogram the chip in real-time. Xilinx took a different approach. It developed a cache memory on the chip that allows the processor to access nanosecond configuration data. In addition, it stores frequently used configuration templates, reducing the number of times the device must access external memory.