Implementation of Soft-core Processor on FPGAGROUP 8 :

N IKHIL SHAH

NIRMIT PATEL

SARTHAK GANDHI

DEEPAKKUMAR PRAJAPATI

Project Guide:Rahul V Mehta

Abstract• Hard-core processor are fixed and cannot be changed while soft-core processors Can be easily modified and tuned to specific requirements, more features, custom instructions, etc.

• In soft-core processor Multiple cores can be used.

• We can add a soft-core processor to a FPGA-based system after it's already designed. However, adding a hard-core processor requires either a different FPGA, or an additional chip on the board.

• All the major FPGA vendors have soft-core processors in their product offerings and there are also a number of companies and organizations developing soft-core processors and can be implemented in any FPGA design.

• Thus, due to following advantages of Soft-core processor over other types of processors we have decided to work on Soft-core processor.

Implementation of Soft-Core Processor on FPGA

Phase I (Language Survey)• Study of Basic VHDL Programming Language.

• Learn the basics of Xilinx and implement simple programs to understand the working of each stage.

• Study of Soft-core Processor – PicoBlaze.

• The KCPSM3 Assembler.

• Study the methods of Handshaking to implement multi-core processor and decide one of them.

Implementation of Soft-Core Processor on FPGA

Phase II• Implement the selected method of Handshaking on FPGA Board Spartan 3E.

• Make an application of the soft-core processor. For eg. Graphical LCD, Stepper Motor or Sensor Interfacing.

Implementation of Soft-Core Processor on FPGA

Why VHDL?• Is an IEEE and ANSI standard .• Three basic different description styles: structural, dataflow, and

behavioral.• The language supports hierarchy.• Wide range of abstraction levels.• Easier large scale design modeling.• Test benches can be written.• Precise simulation semantics are defined.• Capability of defining new data types.

Implementation of Soft-Core Processor on FPGA

PicoBlaze• The most popular and widely-used cores (of Xilinx Incorporated) are

the MicroBlaze and PicoBlaze soft-core processors.• The PicoBlaze microcontroller is a compact, capable, and cost-

effective fully embedded 8-bit RISC microcontroller core optimized for the Xilinx FPGA families.• The KCPSM3 version used in this project occupies just 96 FPGA slices

in a Spartan-3 Generation FPGA (which is only 12.5% of an XC3S50 device).• The PicoBlaze microcontroller performs a respectable 44 to 100

million instructions per second (MIPS) depending on the target FPGA family and speed grade.

Implementation of Soft-Core Processor on FPGA

PicoBlaze Key Features

• Supports Virtex-7, Kintex-7, Spartan-3E and older Xilinx FPGA families

• 16 byte-wide general-purpose data registers

• 1K instructions of programmable on-chip program store

• Byte-wide Arithmetic Logic Unit (ALU) with CARRY and ZERO indicator flags

• 256 input and 256 output ports & up to 240MHz performance

• Highly integrated for implementing non-time critical state machine

• Predictable fast interrupt response

Implementation of Soft-Core Processor on FPGA

Interface Of PicoBlaze

KCPSM = Constant(K) Coded Programmable State Machine

• PicoBlaze consists of two parts: 1) the processor core and 2) the program memory from which instructions are fetched and executed by the processor core.

Implementation of Soft-Core Processor on FPGA

KCPSM3 Assembler Files

Implementation of Soft-Core Processor on FPGA

PicoBlaze Instructions

Implementation of Soft-Core Processor on FPGA

Multi-core PicoBlaze• More than one PicoBlaze core can be implemented on FPGA and

communication between them can be made using any effective handshake technique.• The major Handshake Techniques are as follows:

Direct handshakeHandshake Based on Reconfigurable MeshMaster-Slave techniqueWrap technique

Implementation of Soft-Core Processor on FPGA

References• Download PicoBlaze reference designs and additional files.

http://www.xilinx.com/ipcenter/processor_central/picoblaze

• Xilinx System Generator User Guide: “Designing PicoBlaze Microcontroller Applications”

http://www.xilinx.com/support/sw_manuals/sysgen_ug.pdf

•Mehta Rahul V. “Implementation of PicoBlaze on Xilinx's Spartan 3E FPGA”, International Journal of Computer and Electronics engineering Volume 4 Number 2(July-Dec 2012).

• J. Bhaskar “A VHDL Primer”.

•Volnei A. Pedroni “Circuit Design with VHDL”, Massachusetts Institute of Technology, 2004.

•Heiner Giefers and Marco Platzner “A Many-core Implementation Based On The Reconfigurable Mesh Model ”, University of Paderborn.

Thanks for your attention.

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