MicroBlaze Processor

Prepared By:Krunal Siddhapathak(10BEC097)

Presentation outline

1. Introduction 2. MicroBlaze Core Block Diagram

3. MicroBlaze Architecture 4. Features

5. Advantages6. Architecture limitations of MicroBlaze

7. Conclusion

Introduction» The MicroBlaze is a soft processor core designed for

Xilinx FPGAs from Xilinx. » embedded processor soft core is a reduced

instruction set computer (RISC) .» A soft microprocessor (also called soft core

microprocessor or a soft processor) is a microprocessor core that can be wholly implemented using logic synthesis.

MicroBlaze core Block diagram

MicroBlaze Architecture» Supports two Bus Standards. 1) PLB V46 (PROCESSOR LOCAL BUS) 2) XILINX LOCAL MEMORY BUS» LMB designed to interface local PLBs block designed

in FPGA.» PLB V46 designed for High speed and High

Bandwidth peripherals.» PLB V46 supports 128bits of data and 36 bits of

address.

MicroBlaze Architecture» MicroBlaze By default do not supports any Cache

blocks.» When it gets activated by EDK(Embedded

development Kit) cache block also gets activated through BLOCK RAM.

» There are mainly Two Types of RAMS 1) BLOCK RAM 2) Distributed RAM» Supports FAST Simplex Link (FSL).» FSL is used for Custom Function like large

multiplication etc.

MicroBlaze Architecture» Supports Tightly coupled OFF chip FLSH/SRAM

Memory.» Used to provide low latency memory access that is

known as Cache link with interfering PLB V46» Some embedded system like Power PC contains 1) PLB V46 master bus 2)PLB V46 slave bus.» Less time intensive task can be off loaded to slave

bus that is also connected to MicroBlaze core.

MicroBlaze Architecture

Features» highly configurable processor, allowing you to

select a specific set of features required by your design.

» The fixed feature set of the processor includes:˃ Thirty-two 32-bit general purpose registers˃ 32-bit instruction word with three operands and two addressing modes˃ 32-bit address bus˃ Single issue pipeline

In addition to these fixed features, the MicroBlaze processor is parameterized to allow selective enabling of additional functionality. Older (deprecated) versions of MicroBlaze support a subset of the optional features. Only the latest (preferred) version of MicroBlaze (v7.1) supports all options.

Features(Contd.)» In terms of its instruction-set architecture, MicroBlaze is very similar to

the RISC-based DLX architecture.» The MicroBlaze has a versatile interconnect system to support a variety of

embedded applications.» A newer version of the MicroBlaze, supported in both Spartan-6 and

Virtex-6 implementations, as well as the 7-Series, supports the AXI specification.

» The majority of vendor-supplied and third-party IP interface to PLB directly (or through an PLB to OPB bus bridge.)

» For access to local-memory (FPGA BRAM), MicroBlaze uses a dedicated LMB bus, which reduces loading on the other buses.

» User-defined coprocessors are supported through a dedicated FIFO-style connection called FSL (Fast Simplex Link).

» The coprocessor(s) interface can accelerate computationally intensive algorithms by offloading parts or the entirety of the computation to a user-designed hardware module.

Advantage» Easy to use with EDK˃ Linux/GCC support (with limitations)

» High “performance” soft core processor˃ Most of instructions can be completed with 1 cycles˃ Shorter pipeline, higher working frequency (>100 MHz on

Virtex-II )+ LEON3 7-stage pipeline, 5000 LUTs @ 90MHz on Virtex-II

˃ FPGA optimized implementation+ Fast carry chain MUX, hardware multiplier+ RLOC placement constraints

Advantage» MicroBlaze Core Features and Options

˃ Low Latency Interrupt Mode˃ Fault Tolerance, including Error Correction Codes (ECC) and Lockstep

support˃ LMB BRAM memory˃ Parity protection on internal BRAMs and caches˃ Floating Point Unit (FPU)˃ IEEE 754 compatible˃ Single precision˃ Memory Management Unit (MMU)˃ Full MMU with Virtual Memory supported by Linux˃ MPU mode for region protection for secure RTOS applications˃ Instruction and Data Caches˃ Cache size configurable: 2kB - 64kB (Block RAM based)

Advantage» New version 8 features expand MicroBlaze capabilities even further

˃ Relocatable base vector addresses for maximum memory sharing flexibility when using MicroBlaze in Zynq-7000 AP SoC devices

˃ New Sleep instruction enhances MicroBlaze low-power performance˃ IO Module enhancements add GPI interrupts, and programmable UART

baud rate. Can be used with either MicroBlaze_MCS or full MicroBlaze˃ LMB BRAM interface controller now supports multiple LMB busses˃ New low latency interrupts where the controller directly supplies the

interrupt vector for each individual interrupt, lowering latency response by as much as 10X depending on system design.

˃ Embedded designers can now add a new AXI System Cache soft-peripheral to any memory controller-based design. MicroBlaze then uses this peripheral as Level 2 cache increasing system performance even further.

˃ New byteswap instructions to further increase Ethernet performance when using AXI.

»

Advantage» Simplify your life - MicroBlaze Configuration Wizard

˃ Extreme configurability is at the heart of Micro Blaze’s flexibility, but you don’t have to memorize a manual to learn how to configure MicroBlaze.

˃ Through the MicroBlaze Configuration Wizard included in Xilinx Platform Studio – a few mouse clicks lets you quickly select between six common microprocessor use models.

˃ The configuration wizard delivers instant feedback through a meter display on resource utilization and performance, and runs in wizard mode for fast setup, or advanced mode for access to the lowest level details.

» Smaller, but still powerful - MicroBlaze Microcontroller System˃ Xilinx also offers the power of MicroBlaze in an even smaller package - MicroBlaze

Micro Controller System .˃ MicroBlaze MCS consists of MicroBlaze in a fixed 3-stage pipeline configuration for the

smallest footprint surrounded by a system of common embedded design peripherals.˃ it can run from IDS Logic Edition without the need for a full embedded design license.

Architecture limitations of MicroBlaze» No MMU support˃ no protection among processes˃ Can’t run full version Linux.

» No double precision floating point˃ no full floating point libraries support in libC

» No atomic instructions˃ hard to implement lock˃ non-blocking FIFO instruction problem.

» No cache coherent support

EDK(Embedded development Kit)» Xilinx's EDK (Embedded Development Kit) is the development package

for building MicroBlaze (and PowerPC) embedded processor systems in Xilinx FPGAs.

» Designers use XPS (Xilinx Platform Studio) to configure and build the hardware specification of their embedded system (processor core, memory-controller, I/O peripherals, etc.)

» The XPS converts the designer's platform specification into a synthesizable RTL description (Verilog or VHDL), and writes a set of scripts to automate the implementation of the embedded system (from RTL to the bitstream-file.)

» For the MicroBlaze core, the EDK normally generates an encrypted (non human-readable) netlist, but the processor description (written in VHDL) can be purchased from Xilinx.

Conclusion» MicroBlaze™ is the industry-leader in FPGA-

based soft processors, with advanced architecture options like AXI or PLB interface, Memory Management Unit (MMU), instruction and data-side cache, configurable pipeline depth, Floating-Point unit (FPU), and much more.

References» http://

www.xilinx.com/support/documentation/sw_manuals/mb_ref_guide.pdf

» http://www.wiki.xilinx.com/MicroBlaze» http://

www.smdp2vlsi.gov.in/smdp2vlsi/downloads/mb_tutorial.pdf

THANK YOU!!!!