Impact of Hardware/Software Partitioning and MicroBlaze FPGA Configurations on the Embedded Systems Performances - Complex System Modelling and Control Through Intelligent Soft Computations - page 710

Xilinx firm has proposed the Virtex II Pro device with two or more PowerPC and tens

millions of programmable gates and both PicoBlaze and MicroBlaze soft-cores.
OpenCore has presented OpenRISC soft-core (Bolado et al. 2004 ) and Gaisler
Research has given LEON and LEON2 soft-cores (Denning et al. 2004 ). In our study,
the partitioning of software/hardware components was tested on Virtex-5 FPGA
circuit, which allows the integration of various MicroBlaze soft-cores processors. In
this chapter, embedded soft-core processor architecture, as being examined, consists
of the Xilinx MicroBlaze soft-core processor.

3.1 Xilinx MicroBlaze Soft-Core Processor Architecture

Embedded processors can be de ned as software cores implemented in hardware

circuits using Logic General Purpose Programmable. The most used soft-cores
processors, in the designing of embedded system for Xilinx FPGA, is the Xilinx s

MicroBlaze soft-core processor. MicroBlaze is a 32-bit Reduced Instruction Set
Computer (RISC) architecture optimized for synthesis and implementation into
Xilinx FPGAs with a separate 32-bit instruction and data buses to execute programs
and access data from both on-chip and external memory at the same time. This
processor includes 32-bit general-purpose registers, virtual memory management,
cache software support, and FSL interfaces. It has Harvard memory architecture and
uses: Two Local Memory Busses (LMB) for instruction and data memory, two-
Block RAMs (BRAM) and two peripherals connected via On-chip Peripheral Bas
(OPB). Three memory interfaces are supported: Local Memory Bus (LMB), the
IBM Processor Local Bus (PLB), and Xilinx Cache Link (XCL): The LMB offers
single-cycle access to on-chip dual-port block RAM. The PLB interfaces offer a
connection to both on-chip and off-chip peripherals and memory. The CacheLink
interface is proposed for use with specialized external memory controllers. The
architecture of the Xilinx MicroBlaze FPGA processor,

'

the interfaces, buses,

memory, and peripherals are shown in Fig. 4 .
The major advantage of choosing MicroBlaze soft-core processor, in our

researches, is its higher performance and its various con gurations.

3.2 Xilinx MicroBlaze Soft-Core Processor Features

The MicroBlaze Xilinx processor offers tremendous fl flexibility during the design

process. It allows different con gurations to meet the needs of their design

embedded applications by adding or removing some setting parameters such as:

Integer Multiplier Units: Add the Integer multiplication as a co-processor.

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Barrel Shifter Units: Add the Shift by bit operations as a co-processor.

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Integer Divider Units: Add the Division of Integer as a co-processor.

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