Microblaze

1. MicroBlaze Processor Prepared By: Krunal Siddhapathak(10BEC097)

2. Presentation outline

3. 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.

4. MicroBlaze core Block diagra m

5. 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.

6. 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.

7. 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.

8. MicroBlaze Architecture

9. 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.

10. 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 A newer version of the MicroBlaze, supported in both Spartan-6 and Virtex-6 implementations, as well as the 7-Series, supports the AXI specification.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.

11. 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

12. 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)

13. 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.  

14. 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.

15. 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

16. 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.

17. 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.

18. 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

19. THANK YOU!!!!