Embedded Processing Solutions Backgrounder
Embedded Development Kit v9.2
Introduction
Time is a precious resource, whether a designer is racing to gain access to premium price points on the rising edge of a new market window, scrambling to incorporate last-minute changes to accommodate emerging standards, or squeezing every second out of a product life cycle. Building on a flexible hardware platform provides the remarkable capacity to reduce time to market, time to standards implementation, and time to debug and repair, while staving off the natural erosion of product life through commodity valuation, and ultimately, obsolescence.
Field Programmable Gate Arrays (FPGAs) are all about flexibility. The ability to accommodate change, whether to augment, adapt or amend, diversify or differentiate electronic system designs, sets the FPGA apart from all other design platforms. In a world where change is the axiomatic constant that rewards those who are nimble, the FPGA can turn time into an asset rather than a cost, and change into an advantage rather than a burden.
Facing Change with Options
The best way for designers to prepare for change is to arm themselves with options. The FPGA has always provided those options through the programmability of its hardware, but embedded processorshave opened an entirely new set of opportunities to the designer. By integrating most of an embedded system including the processor, peripherals and glue logic into a single chip, embedded designers can reduce total system cost, power and board space by reducing component count. Integrating custom coprocessors on the FPGA can also help accelerate performance-critical portions of their design. Moreover, Xilinx embedded processors and pre-verified IP cores allow designers to focus their efforts on creating differentiated value, thereby getting to market with initial products in time to extract maximum return from diminishing market windows.
The Latest in Xilinx Embedded Processing
In response to the evolving requirements of its target markets, Xilinx has substantially enhanced its embedded processing capabilities by upgrading every aspect of its embedded processing solutions, including processors, peripherals, and system architecture, while drastically simplifying their usage through intuitive hardware and software tools delivered as part of Embedded Development Kits (EDKs).
This next phase in the evolution of FPGA-based embedded processing solutions delivered with EDK v9.2 targets two key customer-focused goals:making software development easier and enablingrapid design of high-performance embedded systems.
Making Software Development Easier
MicroBlaze™ v7 Processor with Configurable MMU
The award-winning MicroBlaze processor is a configurable 32-bit RISC processor soft core optimized for the flexibility inherent to Xilinx FPGAs. The soft processor is uniquely configurable in that a designer can implement only the specific features required by the design, thereby optimizing silicon area and/or performance. Every aspect of the MicroBlaze processor is customizable, including functional requirements like pipeline depths, caches, floating point units, multipliers, dividers and more importantly, the use of optional coprocessors based on the target application. Table 1 shows how the MicroBlaze processior has evolved since its introduction.
Table 1 – MicroBlaze processor evolution
With the new Memory Management Unit (MMU) in the MicroBlaze v7 processor, designers can exploit a full-fledged embedded operating system like Linux, increasing their productivity using its virtual memory capabilities while developing more robust software applications using its memory protection capabilities. Embedded software developers that choose to create their own custom real-time kernels or executives can also configure the MMU to provide only the memory protection function, further reducing the logic area utilized in the FPGA. Note that the MicroBlaze processor ISA is still software-backwards compatible with previous versions of the processor core.
Support for Commercial-Grade Linux RTOS
Xilinx has added support for LynuxWorks’™ Blue Cat Linux 2.6, a robust, commercially supported Real Time Operating System (RTOS). Enabled by the MicroBlaze processor’s new MMU, this is the industry’s only Linux port for FPGA-based soft processors. Now for the first time,embedded designerscan design and optimize their ideal embedded processing system by taking advantage of the full-blown features of a high-end RTOS in combination with the flexible MicroBlaze soft-core processor technology.
Industry Standard Software Debug Tools
Embedded software engineers require a different kind of visibility than that used by hardware engineers, who often identify and fix issues with tools like volt-meters, oscilloscopes and logic analyzers. Rather than searching for hardware events, software engineers prefer to analyze their code looking at functions and software code execution. Software debuggers are required tools for embedded engineers and are used to set breakpoints, stop, start, and step through the code line by line.
Software “Trace” tools allow engineers to capture longer software execution threads to analyze where the problems reside and track them down to final resolution. Using internal system memory to capture information is useful in many cases, but doesn’t help when a defect causes the system to hang or crash. External Trace tools with their own probes and additional memory allow for deeper (longer) trace captures and avoid system memory issues. Industry partners like Lauterbach and Computex provide trace tool support for the MicroBlaze processor.
The Xilinx Platform Studio Software Development Kit (SDK), an industry standard Eclipse-based IDE, provides the same familiar software development environment to which embedded developers have grown accustomed. The MicroBlaze processor is also complemented by support from Xilinx Embedded Ecosystem partners, including leading RTOS and tool vendors
Enhanced system architecture with interconnect and peripherals
As stated before, the key advantage of FPGA-based embedded systems is its flexibility, manifested in the designer’s ability to select the right set of peripherals, customize them to the right feature requirements and connect them in the most optimal way. The latter operation is significantly enhanced with the new 32 to 128-bit CoreConnect™ Processor Local Bus (PLBv46) that supports both MicroBlaze and PowerPC® processor based systems from Xilinx. The new system architecture (Figure 1) supports shared connections as before for smaller implementation area, reducing cost while also supporting point-to-point connections for higher bandwidth needs.
Another key architectural enhancement is the use of a Multi-Port Memory Controller (MPMC) as the centerpiece of high-performance embedded system design with FPGAs. The new MPMC core delivered with the Platform Studio tool suite provides optimal memory throughput by providing the flexibility to select the appropriate external memory from a wide range of SDRAM, DDR or DDR2 DIMM modules or memory chips with data widths from 8 to 64-bits. In addition, MPMC supports up to 8 parameterizable ports with configurable buffering and arbitration to fine tune the system for the highest system throughput.
These architectural enhancements support the use of high-performance hard IP cores embedded in Virtex™-5 FPGAs like the Tri-mode Ethernet MAC (TEMAC) and PCI Express® (PCIe) block. In addition, Xilinx upgraded more than 50 peripherals in EDK to use the single common PLBv46 bus interface, simplifying selection of IP.
Figure 1 – Flexible Embedded System
Platform Studio simplifies high-performance system design
The Xilinx Platform Studio tool suite (XPS) provides guided design wizards to enable customers to build high-performance SoCs in minutes using MicroBlaze or PowerPC processors and the high-performance IP described earlier. For example, using the Base System Builder wizard a designer can quickly create a high-performance networking subsystem that includes the MPMC with built-in Scatter Gather DMA,and aTEMAC with a Dynamic Realignment Engine (DRE) and CheckSum Offload (CSO) that can support TCP/IP payload throughputs greater than 900 Mbps with PowerPC processors. The new clocking wizard in XPS simplifies the setup of multiple Digital Clock Manager (DCM) primitives needed to support the wide range of clock frequencies, which in turn are needed to interface with external I/O and memory interfaces.
Jump-start Embedded System Design
Integrated development kits kick-start design and accelerate the development cycle. The latest MicroBlaze Development Kit, Spartan-3E 1600E Edition, provides a comprehensive kit including MicroBlaze, a board and a complete embedded development suite. Pre-verified references designs, communication cables and a single JTAG probe supporting both FPGA image download and SW/HW debug tools provide the difference between an efficient evaluation platform and a “stand-alone board.”
Intelligent embedded tools with guided wizards make evaluation easy, automating the steps required to set up the board, chose the processor, customize specific IP, and generate matching peripheral drivers as well as sample test code. Using a working FPGA evaluation board and an example design, designers save valuable time by beginning code debugging immediately, rather waiting for new hardware or manufacturing defects to appear.
Xilinx Embedded Processing Solutions Summary
As embedded system design technology has expanded and matured, so has the appetite for new technology exhibited by end users and the applications that serve them. Changes can come swiftly, trends and tipping points often overrunning one’s capacity to accurately and efficiently feed the demand. To meet this demand, Xilinx has introduced the next generation of its Embedded Processing Solutions built to address the need for flexibility, integration and performance in a wide range of markets and applications including the communications, industrial, medical, automotive and defense markets.
The enhanced 32-128 bit CoreConnect Processor Local Bus (PLB) delivers the performance and scalability to satisfynext-generation requirements. In addition, the award-winning MicroBlaze 32-bit processor now includes the industry’s only configurable MMU to enable commercial-grade OS support. A host of upgraded IP and design tools delivered with the Embedded Development Kit (EDK) version 9.2 also supports the MicroBlaze v7 processor.
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