Embedded Design Handbook

Download PDF
ID 683689
Date 8/28/2023
Public
Document Table of Contents
Document Table of Contents x
Product Discontinuance Notification 1. Introduction 2. First Time Designer's Guide 3. Hardware System Design with Intel® Quartus® Prime and Platform Designer 4. Software System Design with a Nios® II Processor 5. Nios® II Configuration and Booting Solutions 6. Nios® II Debug, Verification, and Simulation 7. Optimizing Nios® II Based Systems and Software
1. Introduction x
1.1. Document Revision History for Embedded Design Handbook
2. First Time Designer's Guide x
2.1. FPGAs and Soft-Core Processors 2.2. Embedded System Design 2.3. Embedded Design Resources 2.4. Intel Embedded Glossary 2.5. First Time Designer's Guide Revision History
2.3. Embedded Design Resources x
2.3.1. Intel Embedded Support 2.3.2. Intel Embedded Training 2.3.3. Intel Embedded Documentation 2.3.4. Third Party Intellectual Property
3. Hardware System Design with Intel® Quartus® Prime and Platform Designer x
3.1. FPGA Hardware Design 3.2. System Design with Platform Designer 3.3. Interfacing an External Processor to an Intel FPGA 3.4. Avalon-MM Byte Ordering 3.5. Memory System Design 3.6. Nios® II Hardware Development Tutorial 3.7. Platform Designer System Design Tutorial 3.8. Hardware System Design with Intel® Quartus® Prime and Platform Designer Revision History
3.1. FPGA Hardware Design x
3.1.1. Connecting Your FPGA Design to Your Hardware 3.1.2. Connecting Signals to your Platform Designer System 3.1.3. Constraining Your FPGA-Based Design
3.2. System Design with Platform Designer x
3.2.1. Intel System on a Programmable Chip (Platform Designer) Solutions 3.2.2. Platform Designer Design
3.3. Interfacing an External Processor to an Intel FPGA x
3.3.1. Configuration Options 3.3.2. RapidIO Interface 3.3.3. PCI Express* Interface 3.3.4. PCI Interface 3.3.5. Serial Protocol Interface (SPI) 3.3.6. Custom Bridge Interfaces
3.4. Avalon-MM Byte Ordering x
3.4.1. Endianness 3.4.2. Avalon® -MM Interface Ordering 3.4.3. Nios® II Processor Data Accesses 3.4.4. Adapting Processor Masters to be Avalon-MM Compliant 3.4.5. System-Wide Design Recommendations
3.4.1. Endianness x
3.4.1.1. Hardware Endianness 3.4.1.2. Software Endianness
3.4.2. Avalon® -MM Interface Ordering x
3.4.2.1. Dynamic Bus Sizing DMA Examples
3.4.4. Adapting Processor Masters to be Avalon-MM Compliant x
3.4.4.1. PowerPC Bus Byte Ordering 3.4.4.2. ARM BE-32 Bus Byte Ordering 3.4.4.3. ARM BE-8 Bus Byte Ordering 3.4.4.4. Other Processor Bit and Byte Orders 3.4.4.5. Arithmetic Byte Reordering
3.4.5. System-Wide Design Recommendations x
3.4.5.1. System-Wide Arithmetic Byte Ordering 3.4.5.2. System-Wide Arithmetic Byte Reordering in Software
3.5. Memory System Design x
3.5.1. Memory Types 3.5.2. On-Chip Memory 3.5.3. External SRAM 3.5.4. Flash Memory 3.5.5. SDRAM 3.5.6. Case Study
3.5.1. Memory Types x
3.5.1.1. Volatile Memory 3.5.1.2. Non-Volatile Memory
3.5.2. On-Chip Memory x
3.5.2.1. Advantages 3.5.2.2. Disadvantages 3.5.2.3. Best Applications 3.5.2.4. Poor Applications 3.5.2.5. On-Chip Memory Types 3.5.2.6. Best Practices
3.5.2.3. Best Applications x
3.5.2.3.1. Cache 3.5.2.3.2. Tightly Coupled Memory 3.5.2.3.3. Look Up Tables 3.5.2.3.4. FIFO
3.5.3. External SRAM x
3.5.3.1. Advantages 3.5.3.2. Disadvantages 3.5.3.3. Best Applications 3.5.3.4. Poor Applications 3.5.3.5. External SRAM Types 3.5.3.6. Best Practices
3.5.4. Flash Memory x
3.5.4.1. Advantages 3.5.4.2. Disadvantages 3.5.4.3. Typical Applications 3.5.4.4. Poor Applications 3.5.4.5. Flash Types
3.5.5. SDRAM x
3.5.5.1. Advantages 3.5.5.2. Disadvantages 3.5.5.3. Best Applications 3.5.5.4. Poor Applications 3.5.5.5. SDRAM Types 3.5.5.6. SDRAM Controller Types Available From Intel 3.5.5.7. Best Practices
3.5.5.7. Best Practices x
3.5.5.7.1. Half-Rate Mode 3.5.5.7.2. Full-Rate Mode 3.5.5.7.3. Sequential Access 3.5.5.7.4. Bursting 3.5.5.7.5. SDRAM Minimum Frequency 3.5.5.7.6. SDRAM Device Speed
3.5.6. Case Study x
3.5.6.1. Application Description 3.5.6.2. Initial Memory Partitioning 3.5.6.3. Optimized Memory Partitioning
3.5.6.3. Optimized Memory Partitioning x
3.5.6.3.1. Add an External SRAM for Input Buffers 3.5.6.3.2. Add On-Chip Memory for Video Line Buffers
3.6. Nios® II Hardware Development Tutorial x
3.6.1. Software and Hardware Requirements 3.6.2. Intel® FPGA IP Evaluation Mode 3.6.3. Nios® II Design Example 3.6.4. Nios® II System Development Flow 3.6.5. Creating the Design Example
3.6.4. Nios® II System Development Flow x
3.6.4.1. Analyzing System Requirements 3.6.4.2. Defining and Generating the System in Platform Designer 3.6.4.3. Integrating the Platform Designer System into the Intel® Quartus® Prime Project 3.6.4.4. Developing Software with the Nios® II Software Build Tools for Eclipse 3.6.4.5. Running and Debugging Software on the Target Board 3.6.4.6. Varying the Development Flow
3.6.5. Creating the Design Example x
3.6.5.1. Install the Design Files 3.6.5.2. Analyze System Requirements 3.6.5.3. Start the Intel® Quartus® Prime Software and Open the Example Project 3.6.5.4. Create a New Platform Designer System 3.6.5.5. Define the System in Platform Designer 3.6.5.6. Integrate the Platform Designer System into the Intel® Quartus® Prime Project 3.6.5.7. Download the Hardware Design to the Target FPGA 3.6.5.8. Develop Software Using the Nios® II SBT for Eclipse 3.6.5.9. Run the Program on Target Hardware
3.6.5.5. Define the System in Platform Designer x
3.6.5.5.1. Specify Target FPGA and Clock Settings 3.6.5.5.2. Add the On-Chip Memory 3.6.5.5.3. Add the Nios® II Processor Core 3.6.5.5.4. Add the JTAG UART 3.6.5.5.5. Add the Interval Timer 3.6.5.5.6. Add the System ID Peripheral 3.6.5.5.7. Add the PIO 3.6.5.5.8. Specify Base Addresses and Interrupt Request Priorities 3.6.5.5.9. Generate the Platform Designer System
3.6.5.6. Integrate the Platform Designer System into the Intel® Quartus® Prime Project x
3.6.5.6.1. Instantiate the Platform Designer System Module in the Intel® Quartus® Prime Project 3.6.5.6.2. Add IP Variation File 3.6.5.6.3. Assign FPGA Device 3.6.5.6.4. Assign FPGA Pin Locations 3.6.5.6.5. Set Timing 3.6.5.6.6. Compile the Intel® Quartus® Prime Project and Verify Timing
3.6.5.8. Develop Software Using the Nios® II SBT for Eclipse x
3.6.5.8.1. Create a New Nios® II Application and BSP from Template 3.6.5.8.2. Compile the Project
3.7. Platform Designer System Design Tutorial x
3.7.1. Software and Hardware Requirements 3.7.2. Download and Install the Tutorial Design Files 3.7.3. Open the Tutorial Project 3.7.4. Creating Platform Designer Systems 3.7.5. Assemble a Hierarchical System 3.7.6. Viewing the Memory Tester System in Platform Designer 3.7.7. Compiling and Downloading Software to a Development Board 3.7.8. Debugging Your Design 3.7.9. Verifying Hardware in System Console 3.7.10. Simulating Custom Components 3.7.11. View a Diagram of the Completed System
3.7.4. Creating Platform Designer Systems x
3.7.4.1. Create a Data Pattern Generator Platform Designer System 3.7.4.2. Create a Data Pattern Checker Platform Designer System
3.7.4.1. Create a Data Pattern Generator Platform Designer System x
3.7.4.1.1. Create a New Platform Designer System and Set up the Clock Source 3.7.4.1.2. Add a Pipeline Bridge 3.7.4.1.3. Add a Custom Pattern Generator 3.7.4.1.4. Add a PRBS Pattern Generator 3.7.4.1.5. Add a Two-to-One Streaming Multiplexer 3.7.4.1.6. Verify the Memory Address Map 3.7.4.1.7. Connect the Reset Signals 3.7.4.1.8. Save the System
3.7.4.2. Create a Data Pattern Checker Platform Designer System x
3.7.4.2.1. Create a New Platform Designer System and Set Up the Clock Source 3.7.4.2.2. Add a Pipeline Bridge 3.7.4.2.3. Add a Custom Pattern Checker 3.7.4.2.4. Add the PRBS Pattern Checker 3.7.4.2.5. Add a One-to-Two Streaming Demultiplexer 3.7.4.2.6. Verify the Memory Address Map 3.7.4.2.7. Connect the Reset Signals 3.7.4.2.8. Save the System
3.7.5. Assemble a Hierarchical System x
3.7.5.1. Create the Hierarchical Memory Tester System 3.7.5.2. Complete the Top-Level System
3.7.5.1. Create the Hierarchical Memory Tester System x
3.7.5.1.1. Add the Pattern Generator 3.7.5.1.2. Add the Pattern Checker 3.7.5.1.3. Add Memory Master Components 3.7.5.1.4. Connect the Reset Signals 3.7.5.1.5. Verify the Memory Address Map 3.7.5.1.6. Save the System
3.7.9. Verifying Hardware in System Console x
3.7.9.1. Open the Tutorial Project 3.7.9.2. Add the JTAG-to- Avalon® Master Bridge 3.7.9.3. Debug with System Console
3.7.10. Simulating Custom Components x
3.7.10.1. Generate a Testbench System in Platform Designer 3.7.10.2. Run Simulation In the ModelSim Software
3.7.10.1. Generate a Testbench System in Platform Designer x
3.7.10.1.1. Create a New Platform Designer System for the Design Under Test 3.7.10.1.2. Export Design Under Test 3.7.10.1.3. Generate a Testbench System 3.7.10.1.4. Generate Testbench System's Simulation Models
3.7.10.2. Run Simulation In the ModelSim Software x
3.7.10.2.1. Set Up the Simulation Environment 3.7.10.2.2. Run the Simulation
4. Software System Design with a Nios® II Processor x
4.1. Nios® II Command-Line Tools 4.2. Developing Nios® II Software 4.3. Nios® II MPU Usage 4.4. Profiling Nios® II Systems 4.5. Software System Design with a Nios® II Processor Revision History
4.1. Nios® II Command-Line Tools x
4.1.1. Intel Command-Line Tools for Board Bringup and Diagnostics 4.1.2. Intel Command-Line Tools for Flash Programming 4.1.3. Intel Command-Line Tools for Software Development and Debug 4.1.4. Intel Command-Line Nios® II Software Build Tools 4.1.5. Rebuilding Software from the Command Line 4.1.6. GNU Command-Line Tools
4.1.1. Intel Command-Line Tools for Board Bringup and Diagnostics x
4.1.1.1. jtagconfig 4.1.1.2. nios2-configure-sof 4.1.1.3. system-console
4.1.1.1. jtagconfig x
4.1.1.1.1. jtagconfig Usage Example
4.1.1.2. nios2-configure-sof x
4.1.1.2.1. nios2-configure-sof Usage Example
4.1.2. Intel Command-Line Tools for Flash Programming x
4.1.2.1. nios2-flash-programmer 4.1.2.2. elf2flash, bin2flash, and sof2flash
4.1.2.1. nios2-flash-programmer x
4.1.2.1.1. nios2-flash-programmer Usage Example
4.1.2.2. elf2flash, bin2flash, and sof2flash x
4.1.2.2.1. bin2flash Usage Example
4.1.3. Intel Command-Line Tools for Software Development and Debug x
4.1.3.1. nios2-terminal 4.1.3.2. nios2-download 4.1.3.3. nios2-stackreport 4.1.3.4. validate_zip 4.1.3.5. nios2-gdb-server
4.1.3.2. nios2-download x
4.1.3.2.1. nios2-download Usage Example
4.1.3.3. nios2-stackreport x
4.1.3.3.1. nios2-stackreport Usage Example
4.1.3.4. validate_zip x
4.1.3.4.1. validate_zip Usage Example
4.1.3.5. nios2-gdb-server x
4.1.3.5.1. nios2-gdb-server Usage Example
4.1.4. Intel Command-Line Nios® II Software Build Tools x
4.1.4.1. BSP Related Tools 4.1.4.2. Application Related Tools
4.1.6. GNU Command-Line Tools x
4.1.6.1. nios2-elf-addr2line 4.1.6.2. nios2-elf-gdb 4.1.6.3. nios2-elf-readelf 4.1.6.4. nios2-elf-ar 4.1.6.5. Linker 4.1.6.6. nios2-elf-size 4.1.6.7. nios2-elf-strings 4.1.6.8. nios2-elf-strip 4.1.6.9. nios2-elf-gdbtui 4.1.6.10. nios2-elf-gprof 4.1.6.11. nios2-elf-gcc and g++ 4.1.6.12. nios2-elf-c++filt 4.1.6.13. nios2-elf-nm 4.1.6.14. nios2-elf-objcopy 4.1.6.15. nios2-elf-objdump 4.1.6.16. nios2-elf-ranlib
4.1.6.1. nios2-elf-addr2line x
4.1.6.1.1. nios2-elf-addr2line Usage Example
4.1.6.3. nios2-elf-readelf x
4.1.6.3.1. nios2-elf-readelf Usage Example
4.1.6.4. nios2-elf-ar x
4.1.6.4.1. nios2-elf-ar Usage Example
4.1.6.5. Linker x
4.1.6.5.1. Linker Usage Example
4.1.6.6. nios2-elf-size x
4.1.6.6.1. nios2-elf-size Usage Example
4.1.6.7. nios2-elf-strings x
4.1.6.7.1. nios2-elf-strings Usage Example
4.1.6.8. nios2-elf-strip x
4.1.6.8.1. nios2-elf-strip Usage Example 4.1.6.8.2. nios2-elf-strip Usage Notes
4.1.6.11. nios2-elf-gcc and g++ x
4.1.6.11.1. Compilation Command Usage Example 4.1.6.11.2. More Complex Compilation Example
4.1.6.12. nios2-elf-c++filt x
4.1.6.12.1. nios2-elf-c++filt Usage Example 4.1.6.12.2. More Complex nios2-elf-c++filt Example
4.1.6.13. nios2-elf-nm x
4.1.6.13.1. nios2-elf-nm Usage Example 4.1.6.13.2. More Complex nios2-elf-nm Example
4.1.6.14. nios2-elf-objcopy x
4.1.6.14.1. nios2-elf-objcopy Usage Example
4.1.6.15. nios2-elf-objdump x
4.1.6.15.1. nios2-elf-objdump Usage Description
4.2. Developing Nios® II Software x
4.2.1. Software Development Cycle 4.2.2. Software Project Mechanics 4.2.3. Developing With the Hardware Abstraction Layer 4.2.4. Linking Applications
4.2.1. Software Development Cycle x
4.2.1.1. Nios® II Software Design 4.2.1.2. Nios® II Software Development Process
4.2.1.1. Nios® II Software Design x
4.2.1.1.1. Nios® II Tools Overview 4.2.1.1.2. Nios® II Software Build Tools
4.2.2. Software Project Mechanics x
4.2.2.1. Software Tools Background 4.2.2.2. Development Flow Guidelines 4.2.2.3. Nios® II Software Build Tools 4.2.2.4. Configuring BSP and Application Projects 4.2.2.5. Ensuring Software Project Coherency
4.2.2.3. Nios® II Software Build Tools x
4.2.2.3.1. The Nios® II Software Build Tools for Eclipse 4.2.2.3.2. The Nios® II Software Build Tools Command Line
4.2.2.4. Configuring BSP and Application Projects x
4.2.2.4.1. Software Example Designs 4.2.2.4.2. Selecting the Operating System (HAL versus MicroC/OS-II RTOS) 4.2.2.4.3. Configuring the BSP Project 4.2.2.4.4. Configuring the Application Project 4.2.2.4.5. Makefiles and the Nios® II Software Build Tools for Eclipse 4.2.2.4.6. Building and Running the Software in Nios® II Software Build Tools for Eclipse
4.2.2.5. Ensuring Software Project Coherency x
4.2.2.5.1. Recommended Development Practice 4.2.2.5.2. Recommended Architecture Practice
4.2.3. Developing With the Hardware Abstraction Layer x
4.2.3.1. Overview of the HAL 4.2.3.2. System Startup in HAL-Based Applications 4.2.3.3. HAL Peripheral Services 4.2.3.4. Accessing Memory With the Nios® II Processor 4.2.3.5. Handling Exceptions 4.2.3.6. Modifying the Exception Handler
4.2.3.1. Overview of the HAL x
4.2.3.1.1. HAL Configuration Options 4.2.3.1.2. Configuring the Boot Environment 4.2.3.1.3. Controlling HAL Initialization 4.2.3.1.4. Minimizing the Code Footprint and Increasing Performance 4.2.3.1.5. Configuring Peripherals and Services
4.2.3.2. System Startup in HAL-Based Applications x
4.2.3.2.1. System Initialization 4.2.3.2.2. crt0 Initialization 4.2.3.2.3. HAL Initialization
4.2.3.3. HAL Peripheral Services x
4.2.3.3.1. Timers 4.2.3.3.2. Character Mode Devices 4.2.3.3.3. Flash Memory Devices 4.2.3.3.4. Direct Memory Access Devices 4.2.3.3.5. Files and File Systems 4.2.3.3.6. Unsupported Devices
4.2.3.4. Accessing Memory With the Nios® II Processor x
4.2.3.4.1. Creating General C/C++ Applications 4.2.3.4.2. Accessing Peripherals 4.2.3.4.3. Sharing Uncached Memory 4.2.3.4.4. Sharing Memory With Cache Performance Benefits
4.2.4. Linking Applications x
4.2.4.1. Background 4.2.4.2. Linker Sections and Application Configuration 4.2.4.3. HAL Linking Behavior
4.2.4.3. HAL Linking Behavior x
4.2.4.3.1. Default BSP Linking 4.2.4.3.2. User-Controlled BSP Linking
4.3. Nios® II MPU Usage x
4.3.1. Requirements 4.3.2. General Usage 4.3.3. Nios® II MPU Design Examples
4.3.2. General Usage x
4.3.2.1. Adding the MPU Hardware 4.3.2.2. Writing Software for the MPU
4.3.2.2. Writing Software for the MPU x
4.3.2.2.1. MPU Programming Guidelines 4.3.2.2.2. Operating Systems and the MPU 4.3.2.2.3. MPU Register Details 4.3.2.2.4. Flow Summary
4.3.3. Nios® II MPU Design Examples x
4.3.3.1. Working with the MPU Design Examples 4.3.3.2. Example Hardware 4.3.3.3. Region Layout Considerations 4.3.3.4. Software
4.3.3.4. Software x
4.3.3.4.1. MPU Utilities 4.3.3.4.2. Building the Software
4.4. Profiling Nios® II Systems x
4.4.1. Requirements 4.4.2. Tools 4.4.3. Using the GNU Profiler to Measure Code Performance 4.4.4. Using Performance Counter and Timer Components 4.4.5. Troubleshooting
4.4.1. Requirements x
4.4.1.1. Obtaining the Hardware Design 4.4.1.2. Obtaining the Software Examples
4.4.2. Tools x
4.4.2.1. GNU Profiler 4.4.2.2. Intel Performance Counter 4.4.2.3. High-Resolution Timer 4.4.2.4. Program Counter Trace Information
4.4.3. Using the GNU Profiler to Measure Code Performance x
4.4.3.1. GNU Profiler Advantages 4.4.3.2. GNU Profiler Limitations 4.4.3.3. Software Considerations 4.4.3.4. Hardware Considerations 4.4.3.5. Tutorial: Using the GNU Profiler
4.4.3.3. Software Considerations x
4.4.3.3.1. Profiler Mechanics 4.4.3.3.2. Profiler Overhead
4.4.3.5. Tutorial: Using the GNU Profiler x
4.4.3.5.1. Profiler Example with the Nios® II Command Line 4.4.3.5.2. Profiler Example with Nios® II SBT for Eclipse 4.4.3.5.3. Analyzing the GNU Profiler Report
4.4.4. Using Performance Counter and Timer Components x
4.4.4.1. Performance Counter Advantages 4.4.4.2. Timer Advantages 4.4.4.3. Performance Counter and Timer Hardware Considerations 4.4.4.4. Performance Counter and Timer Software Considerations 4.4.4.5. Performance Counter Software Considerations 4.4.4.6. The Global Counter 4.4.4.7. Hardware Considerations 4.4.4.8. Tutorial: Using Performance Counters and Timers
4.4.4.8. Tutorial: Using Performance Counters and Timers x
4.4.4.8.1. Modifying the Nios® II Hardware Design 4.4.4.8.2. Programming the Hardware Design to Your Device 4.4.4.8.3. Performance Counter Example with the Nios® II Command Line 4.4.4.8.4. Performance Counter Example with Nios® II SBT for Eclipse 4.4.4.8.5. Analyzing the Performance Counter Report
4.4.5. Troubleshooting x
4.4.5.1. nios2-elf-gprof –annotated-source Switch Has No Effect 4.4.5.2. Writing to the Registers of a Nonexistent Section Counter 4.4.5.3. Output From a printf() or perf_print_formatted_output() Call Near the End 4.4.5.4. Fitting a Performance Counter in a Hardware Design That Consumes Most 4.4.5.5. The Histogram for the gmon.out File Is Missing, Even Though My main()
5. Nios® II Configuration and Booting Solutions x
5.1. Introduction 5.2. Nios® II Processor Booting Methods 5.3. Alternative Nios® II Boot Methods 5.4. Boot Time Performance Analysis 5.5. Nios® II Configuration and Booting Solutions Revision History
5.1. Introduction x
5.1.1. Prerequisites
5.2. Nios® II Processor Booting Methods x
5.2.1. Introduction to Nios® II Booting Methods 5.2.2. Nios® II Processor Booting from On-Chip Flash (UFM) 5.2.3. Nios® II Processor Booting from EPCQ Flash 5.2.4. Nios® II Processor Booting from QSPI Flash 5.2.5. Nios® II Processor Booting from On-Chip Memory (OCRAM) 5.2.6. Nios® II Processor Booting from CFI Flash 5.2.7. Summary of Nios® II Processor Vector Configurations and BSP Settings
5.2.1. Introduction to Nios® II Booting Methods x
5.2.1.1. Nios® II Processor Application Execute-In-Place from Boot Flash 5.2.1.2. Nios® II Processor Application Copied from Boot Flash to RAM Using Boot Copier 5.2.1.3. Nios® II Processor Application Execute-In-Place from OCRAM
5.2.1.1. Nios® II Processor Application Execute-In-Place from Boot Flash x
5.2.1.1.1. alt_load ()
5.2.1.2. Nios® II Processor Application Copied from Boot Flash to RAM Using Boot Copier x
5.2.1.2.1. Memcpy-based Boot Copier
5.2.2. Nios® II Processor Booting from On-Chip Flash (UFM) x
5.2.2.1. Intel® MAX® 10 FPGA On-Chip Flash Description 5.2.2.2. Nios® II Processor Application Execute-In-Place from UFM 5.2.2.3. Nios® II Processor Application Copied from UFM to RAM using Boot Copier
5.2.2.2. Nios® II Processor Application Execute-In-Place from UFM x
5.2.2.2.1. Hardware Design 5.2.2.2.2. Application 5.2.2.2.3. Programming
5.2.2.3. Nios® II Processor Application Copied from UFM to RAM using Boot Copier x
5.2.2.3.1. Hardware Design 5.2.2.3.2. Application 5.2.2.3.3. Programming
5.2.3. Nios® II Processor Booting from EPCQ Flash x
5.2.3.1. Intel FPGA Serial Flash Controller (EPCQ) Overview 5.2.3.2. Nios® II Processor Design, Configuration, and Boot Flow 5.2.3.3. Nios® II Processor Application Execute-In-Place from EPCQ Flash 5.2.3.4. Nios® II Processor Application Copied from EPCQ Flash to RAM Using Boot Copier 5.2.3.5. EPCQ HAL Driver
5.2.3.3. Nios® II Processor Application Execute-In-Place from EPCQ Flash x
5.2.3.3.15.2.3.4.1. Hardware Design5.2.3.3.15.2.3.4.1. Hardware Design 5.2.3.3.2. Application 5.2.3.3.3. Programming
5.2.3.4. Nios® II Processor Application Copied from EPCQ Flash to RAM Using Boot Copier x
5.2.3.3.15.2.3.4.1. Hardware Design5.2.3.3.15.2.3.4.1. Hardware Design 5.2.3.4.2. Application 5.2.3.4.3. Programming
5.2.4. Nios® II Processor Booting from QSPI Flash x
5.2.4.1. Nios® II Processor Design, Configuration and Boot Flow 5.2.4.2. Nios® II Processor Application Executes In-Place from General Purpose QSPI Flash ( Intel® MAX® 10) 5.2.4.3. Nios® II Processor Application Copied from General Purpose QSPI Flash to RAM Using Boot Copier ( Intel® MAX® 10) 5.2.4.4. Nios® II Processor Application Executes In-Place from Configuration QSPI Flash (Other FPGA devices) 5.2.4.5. Nios® II Processor Application Copied from Configuration QSPI Flash to RAM Using Boot Copier (Other FPGA devices)
5.2.4.2. Nios® II Processor Application Executes In-Place from General Purpose QSPI Flash ( Intel® MAX® 10) x
5.2.4.2.1. Hardware Design 5.2.4.2.2. Application 5.2.4.2.3. Programming Files Generation 5.2.4.2.4. QSPI Flash Programming
5.2.4.3. Nios® II Processor Application Copied from General Purpose QSPI Flash to RAM Using Boot Copier ( Intel® MAX® 10) x
5.2.4.3.1. Hardware Design 5.2.4.3.2. Application 5.2.4.3.3. Programming Files Generation 5.2.4.3.4. QSPI Flash Programming
5.2.4.4. Nios® II Processor Application Executes In-Place from Configuration QSPI Flash (Other FPGA devices) x
5.2.4.4.1. Hardware Design 5.2.4.4.2. Application 5.2.4.4.3. Programming Files Generation 5.2.4.4.4. QSPI Flash Programming
5.2.4.5. Nios® II Processor Application Copied from Configuration QSPI Flash to RAM Using Boot Copier (Other FPGA devices) x
5.2.4.5.1. Hardware Design 5.2.4.5.2. Application 5.2.4.5.3. Programming Files Generation 5.2.4.5.4. QSPI Flash Programming
5.2.5. Nios® II Processor Booting from On-Chip Memory (OCRAM) x
5.2.5.1. Nios® II Processor Application Executes in-place from OCRAM
5.2.5.1. Nios® II Processor Application Executes in-place from OCRAM x
5.2.5.1.1. Hardware Design 5.2.5.1.2. Application 5.2.5.1.3. Programming
5.2.6. Nios® II Processor Booting from CFI Flash x
5.2.6.1. Description of the Avalon® Tri-State Conduit Components 5.2.6.2. Nios® II Processor Application Execute-In-Place from CFI Flash 5.2.6.3. Nios® II Processor Application Copied from CFI Flash to RAM using Boot Copier
5.2.6.2. Nios® II Processor Application Execute-In-Place from CFI Flash x
5.2.6.2.15.2.6.3.1. Hardware Design5.2.6.2.15.2.6.3.1. Hardware Design Application 5.2.6.2.3. Programming
5.2.6.3. Nios® II Processor Application Copied from CFI Flash to RAM using Boot Copier x
5.2.6.2.15.2.6.3.1. Hardware Design5.2.6.2.15.2.6.3.1. Hardware Design Application 5.2.6.3.3. Programming
5.3. Alternative Nios® II Boot Methods x
5.3.1. Assumptions About the Reader 5.3.2. Implementing a Custom Boot Copier 5.3.3. Default Nios® II Boot Copier 5.3.4. Advanced Boot Copier Example 5.3.5. Implementing the Advanced Boot Copier Example 5.3.6. Small Boot Copier Example 5.3.7. Implementing the Small Boot Copier Example 5.3.8. Debugging Boot Copiers 5.3.9. Externally Controlling the Nios® II Boot Process
5.3.2. Implementing a Custom Boot Copier x
5.3.2.1. Hardware Design Files 5.3.2.2. Software Files
5.3.3. Default Nios® II Boot Copier x
5.3.3.1. Overview of the Default Nios® II Boot Copier 5.3.3.2. The Default CFI Flash Boot Copier 5.3.3.3. The Default EPCS/EPCQ Boot Copier
5.3.4. Advanced Boot Copier Example x
5.3.4.1. Driver Initialization 5.3.4.2. Printing to the JTAG UART 5.3.4.3. Boot Images 5.3.4.4. Boot Methods 5.3.4.5. Preventing Overlapping Data in Flash 5.3.4.6. Boot Copier Code Size
5.3.4.2. Printing to the JTAG UART x
5.3.4.2.1. Preventing Stalls by the JTAG UART 5.3.4.2.2. Reducing Memory Use for Printing
5.3.4.3. Boot Images x
5.3.4.3.1. Boot Image Format 5.3.4.3.2. Boot Image Header Format 5.3.4.3.3. Boot Record Format 5.3.4.3.4. Choosing a Boot Image 5.3.4.3.5. Word Alignment
5.3.4.4. Boot Methods x
5.3.4.4.1. Booting Directly From CFI Flash 5.3.4.4.2. Booting From CFI Flash, Running From On-Chip Memory 5.3.4.4.3. Booting From EPCS/EPCQ Flash, Running From On-Chip Memory 5.3.4.4.4. Setting the Boot Method
5.3.4.5. Preventing Overlapping Data in Flash x
5.3.4.5.1. Overlapping Data in CFI Flash 5.3.4.5.2. Overlapping Data in EPCS/EPCQ Flash
5.3.5. Implementing the Advanced Boot Copier Example x
5.3.5.1. Setting Up the Software Tools and Development Board 5.3.5.2. Creating a Suitable Hardware Design 5.3.5.3. Building the Advanced Boot Copier 5.3.5.4. Building a Test Application to Boot 5.3.5.5. Packing the Test Application in a Boot Record 5.3.5.6. Booting Directly From CFI Flash Memory 5.3.5.7. Booting CFI or EPCS/EPCQ Flash From On-Chip Memory 5.3.5.8. Running the Advanced Boot Copier Example
5.3.5.2. Creating a Suitable Hardware Design x
5.3.5.2.1. Opening the Example Project 5.3.5.2.2. Adding On-chip Boot ROM to the System
5.3.6. Small Boot Copier Example x
5.3.6.1. Small Boot Copier Features 5.3.6.2. Implementation in Nios® II Assembly Language 5.3.6.3. System Initialization 5.3.6.4. Code Size
5.3.7. Implementing the Small Boot Copier Example x
5.3.7.1. Setting Up the Software Tools and Development Board 5.3.7.2. Creating a Suitable Hardware Design 5.3.7.3. Building the Small Boot Copier Using 'make' 5.3.7.4. Building a Test Application to Boot 5.3.7.5. Booting From On-Chip Memory 5.3.7.6. Running the Small Boot Copier Example
5.3.8. Debugging Boot Copiers x
5.3.8.1. Hardware and Software Breakpoints 5.3.8.2. Enabling Hardware Breakpoints 5.3.8.3. Breaking Before main() 5.3.8.4. Setting Up the Debugger
5.3.9. Externally Controlling the Nios® II Boot Process x
5.3.9.1. Overview 5.3.9.2. Building an Appropriate Platform Designer System 5.3.9.3. The Boot Process
5.3.9.2. Building an Appropriate Platform Designer System x
5.3.9.2.1. External Processor Bridge 5.3.9.2.2. The cpu_resetrequest Signal 5.3.9.2.3. Nios® II Reset Address 5.3.9.2.4. One-Bit PIO Peripheral
5.3.9.3. The Boot Process x
5.3.9.3.1. Boot Images 5.3.9.3.2. Example C Code 5.3.9.3.3. External Boot Flow
5.4. Boot Time Performance Analysis x
5.4.1. Boot Time Performance Analysis Design Example 5.4.2. Boot Time Measurement Strategy 5.4.3. Reducing Nios® II Boot Time in Intel® MAX® 10 FPGA Design 5.4.4. Boot Time Performance and Estimation
5.4.3. Reducing Nios® II Boot Time in Intel® MAX® 10 FPGA Design x
5.4.3.1. Boot Methods 5.4.3.2. Boot Device Performance 5.4.3.3. Peripheral Initialization 5.4.3.4. Nios® II Processor Caches 5.4.3.5. System Speed 5.4.3.6. Intel® MAX® 10 FPGA Nios® II Flash Accelerator
5.4.4. Boot Time Performance and Estimation x
5.4.4.1. Boot Time Performance for Design that Boots from On Chip Flash with Flash Accelerator 5.4.4.2. Boot Time Estimation
6. Nios® II Debug, Verification, and Simulation x
6.1. Software Debugging Options 6.2. Debugging Nios® II Designs 6.3. Verification and Board Bring-Up 6.4. Additional Embedded Design Considerations 6.5. Simulating Nios® II Embedded Processor Designs 6.6. Nios® II Debug, Verification, and Simulation Revision History
6.2. Debugging Nios® II Designs x
6.2.1. Debuggers 6.2.2. Run-Time Analysis Debug Techniques 6.2.3. Using the Debug Code from Intel® MAX® 10 On-Chip Flash - User Flash Memory (UFM)
6.2.1. Debuggers x
6.2.1.1. Nios® II Software Development Tools 6.2.1.2. Signal Tap II Embedded Logic Analyzer 6.2.1.3. Lauterbach Trace32 Debugger and PowerTrace Hardware 6.2.1.4. Data Display Debuggers
6.2.1.1. Nios® II Software Development Tools x
6.2.1.1.1. Nios® II System ID 6.2.1.1.2. Project Templates 6.2.1.1.3. Configuration Options 6.2.1.1.4. Nios® II GDB Console and GDB Commands 6.2.1.1.5. Nios® II Console View and stdio Library Functions 6.2.1.1.6. Importing Projects Created Using the Nios® II Software Build Tools 6.2.1.1.7. Selecting a Processor Instance in a Multiple Processor Design
6.2.2. Run-Time Analysis Debug Techniques x
6.2.2.1. Software Profiling 6.2.2.2. Watchpoints 6.2.2.3. Stack Overflow 6.2.2.4. Hardware Abstraction Layer (HAL) 6.2.2.5. Breakpoints 6.2.2.6. Debugger Stepping and Using No Optimizations
6.2.2.3. Stack Overflow x
6.2.2.3.1. Enabling Run Time Stack Checking
6.2.3. Using the Debug Code from Intel® MAX® 10 On-Chip Flash - User Flash Memory (UFM) x
6.2.3.1. Building Hardware Design in Platform Designer (Standard) 6.2.3.2. Compiling using the Intel® Quartus® Prime 6.2.3.3. Building Software Design 6.2.3.4. Creating the POF File 6.2.3.5. Programming the POF File 6.2.3.6. Debugging the Nios II Software Running in On-Chip Flash
6.3. Verification and Board Bring-Up x
6.3.1. Verification Methods 6.3.2. Board Bring-up 6.3.3. System Verification
6.3.1. Verification Methods x
6.3.1.1. Prerequisites 6.3.1.2. System Console 6.3.1.3. Signal Tap II Embedded Logic Analyzer 6.3.1.4. External Instrumentation 6.3.1.5. Stimuli Generation
6.3.1.4. External Instrumentation x
6.3.1.4.1. Signal Probe Signal Probe 6.3.1.4.2. Logic Analyzer Interface
6.3.2. Board Bring-up x
6.3.2.1. Peripheral Testing 6.3.2.2. Board Testing 6.3.2.3. Minimal Test System
6.3.2.1. Peripheral Testing x
6.3.2.1.1. Data Trace Failure 6.3.2.1.2. Address Trace Failure 6.3.2.1.3. Device Isolation 6.3.2.1.4. JTAG
6.3.3. System Verification x
6.3.3.1. Designing with Verification in Mind 6.3.3.2. Accelerating Verification 6.3.3.3. Using Software to Verify Hardware 6.3.3.4. Environmental Testing
6.4. Additional Embedded Design Considerations x
6.4.1. JTAG Signal Integrity 6.4.2. Memory Space For System Prototyping
6.5. Simulating Nios® II Embedded Processor Designs x
6.5.1. Before You Begin 6.5.2. Setting Up and Generating Your Simulation Environment in Platform Designer 6.5.3. Creating the Nios® II Software 6.5.4. Running Simulation in the ModelSim Simulator Using Nios II SBT for Eclipse 6.5.5. Running Simulation in the ModelSim Simulator Using Command Line
6.5.2. Setting Up and Generating Your Simulation Environment in Platform Designer x
6.5.2.1. Platform Designer-Generated System Simulation Files 6.5.2.2. Memory Simulation Models 6.5.2.3. Using IP and Platform Designer Simulation Setup Scripts
6.5.3. Creating the Nios® II Software x
6.5.3.1. Creating a Software Project Using Nios® II SBT for Eclipse 6.5.3.2. Creating a Software Project Using Command Line
7. Optimizing Nios® II Based Systems and Software x
7.1. Hardware Acceleration and Coprocessing 7.2. Software Application Optimization 7.3. Memory Optimization 7.4. Accelerating Nios® II Networking Applications 7.5. Using Tightly Coupled Memory with the Nios® II Processor Tutorial 7.6. Optimizing Nios® II Based Systems and Software Revision History
7.1. Hardware Acceleration and Coprocessing x
7.1.1. Hardware Acceleration 7.1.2. Coprocessing
7.1.1. Hardware Acceleration x
7.1.1.1. Customizing and Accelerating FPGA Designs 7.1.1.2. Accelerating Cyclic Redundancy Checking (CRC) 7.1.1.3. Creating Nios® II Custom Instructions
7.1.1.2. Accelerating Cyclic Redundancy Checking (CRC) x
7.1.1.2.1. Matching I/O Bandwidths 7.1.1.2.2. Pipelining Algorithms
7.1.2. Coprocessing x
7.1.2.1. Creating Multicore Designs 7.1.2.2. Pre- and Post-Processing 7.1.2.3. Replacing State Machines
7.1.2.1. Creating Multicore Designs x
7.1.2.1.1. Accessing Multiple Nios® II Designs
7.1.2.3. Replacing State Machines x
7.1.2.3.1. Low-Speed State Machines 7.1.2.3.2. High-Speed State Machines 7.1.2.3.3. Subdivided State Machines
7.2. Software Application Optimization x
7.2.1. Performance Tuning Background 7.2.2. Speeding Up System Processing Tasks 7.2.3. Accelerating Interrupt Service Routines 7.2.4. Reducing Code Size
7.2.2. Speeding Up System Processing Tasks x
7.2.2.1. Analyzing the Problem 7.2.2.2. Accelerating your Application
7.2.2.2. Accelerating your Application x
7.2.2.2.1. Increasing Processor Efficiency 7.2.2.2.2. Accelerating Hardware 7.2.2.2.3. Improving Data Movement
7.2.3. Accelerating Interrupt Service Routines x
7.2.3.1. Analyzing the Problem 7.2.3.2. Accelerating the Interrupt Service Routine
7.2.4. Reducing Code Size x
7.2.4.1. Analyzing the Problem 7.2.4.2. Reducing the Code Footprint
7.3. Memory Optimization x
7.3.1. Isolate Critical Memory Connections 7.3.2. Match Master and Slave Data Width 7.3.3. Use Separate Memories to Exploit Concurrency 7.3.4. Understand the Nios® II Instruction Master Address Space 7.3.5. Test Memory
7.4. Accelerating Nios® II Networking Applications x
7.4.1. Downloading the Ethernet Acceleration Design Example 7.4.2. The Structure of Networking Applications 7.4.3. The User Application 7.4.4. Structure of the NicheStack Networking Stack 7.4.5. Ethernet Device 7.4.6. Benchmarking Setup, Results, and Analysis 7.4.7. Nios® II Test Hardware and Test Results
7.4.2. The Structure of Networking Applications x
7.4.2.1. Ethernet System Hierarchy 7.4.2.2. Relationships Between Networking System Elements 7.4.2.3. Finding the Performance Bottlenecks
7.4.3. The User Application x
7.4.3.1. User Application Optimizations
7.4.3.1. User Application Optimizations x
7.4.3.1.1. Software Optimizations 7.4.3.1.2. Hardware Optimizations 7.4.3.1.3. The Sockets API
7.4.4. Structure of the NicheStack Networking Stack x
7.4.4.1. General Optimizations 7.4.4.2. NicheStack Specific Optimizations
7.4.4.2. NicheStack Specific Optimizations x
7.4.4.2.1. NicheStack Thread Priorities 7.4.4.2.2. Disabling Nonessential NicheStack Modules 7.4.4.2.3. Using Faster Packet Memory 7.4.4.2.4. Super Loop Mode 7.4.4.2.5. NicheStack Support and Licensing
7.4.5. Ethernet Device x
7.4.5.1. Link Speed 7.4.5.2. Network Interface (Intel FPGA Triple Speed Ethernet Intel® FPGA IP Function) 7.4.5.3. NicheStack Device Driver Model
7.4.6. Benchmarking Setup, Results, and Analysis x
7.4.6.1. Overview 7.4.6.2. Test Setup 7.4.6.3. Test Methodology 7.4.6.4. Nios® II System Software Configuration 7.4.6.5. Workstation System Software
7.4.6.2. Test Setup x
7.4.6.2.1. Test Systems
7.4.6.3. Test Methodology x
7.4.6.3.1. Ethernet Link Type 7.4.6.3.2. Protocols Tested 7.4.6.3.3. Data Transmission Sizes 7.4.6.3.4. Test Runs
7.4.6.4. Nios® II System Software Configuration x
7.4.6.4.1. NicheStack Networking Stack Configuration 7.4.6.4.2. MicroC/OS-II Configuration 7.4.6.4.3. Benchmark Application 7.4.6.4.4. General Application and System Library Settings
7.5. Using Tightly Coupled Memory with the Nios® II Processor Tutorial x
7.5.1. Reasons for Using Tightly Coupled Memory 7.5.2. Tradeoffs 7.5.3. Guidelines for Using Tightly Coupled Memory 7.5.4. Tightly Coupled Memory Interface 7.5.5. Building a Nios® II System with Tightly Coupled Memory 7.5.6. Generate the Platform Designer System 7.5.7. Run the Tightly Coupled Memories Examples from the Nios® II Command 7.5.8. Program and Run the Tightly Coupled Memory Project 7.5.9. Understanding the Tcl Scripts
7.5.3. Guidelines for Using Tightly Coupled Memory x
7.5.3.1. Hardware Guidelines 7.5.3.2. Software Guidelines
7.5.3.2. Software Guidelines x
7.5.3.2.1. Locating Functions in Tightly Coupled Memory
7.5.4. Tightly Coupled Memory Interface x
7.5.4.1. Restrictions 7.5.4.2. Dual Port Memories
7.5.5. Building a Nios® II System with Tightly Coupled Memory x
7.5.5.1. Hardware and Software Requirements 7.5.5.2. Modify the Example Design to Include Tightly Coupled Memories 7.5.5.3. Create the Tightly Coupled Memories 7.5.5.4. Connect and Position the Tightly Coupled Memories 7.5.5.5. Add a Performance Counter
7.5.9. Understanding the Tcl Scripts x
7.5.9.1. Timer Memory 7.5.9.2. Exception Stack 7.5.9.3. Timer Definitions
7.5.9.3. Timer Definitions x
7.5.9.3.1. peripheral_subsystem_sys_clk_timer 7.5.9.3.2. peripheral_subsystem_high_res_timer
Product Discontinuance Notification
1. Introduction
2. First Time Designer's Guide
3. Hardware System Design with Intel® Quartus® Prime and Platform Designer
4. Software System Design with a Nios® II Processor
5. Nios® II Configuration and Booting Solutions
6. Nios® II Debug, Verification, and Simulation
7. Optimizing Nios® II Based Systems and Software

4.3.2.2.3. MPU Register Details

This section describes the register maps, the meanings of the register fields, and how the register fields are used.

When you initialize the MPU you use two registers: mpubase and mpuacc.

Register mpubase Usage

Table 18.  mpubase Control Register Fields
Bit Fields
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
BASE3
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
BASE3 0 INDEX2 D
Table 19.  mpubase Control Register Field Descriptions
Field Description Access Reset Available
BASE BASE is the base memory address of the region identified by the INDEX and D fields. Read/Write 0 Only with MPU
INDEX INDEX is the region index number. Read/Write 0 Only with MPU
D D is the region access bit. When D =1, INDEX refers to a data region. When D = 0, INDEX refers to an instruction region. Read/Write 0 Only with MPU

You specify an MPU region by writing a value representing the region's base address to the BASE field, a unique index to the INDEX field, and the region type (data or instruction) to field D.

The BASE field represents the region's base address, in the form described by the equation below. The BASE field can only represent addresses aligned to an integer multiple of <min_region>. For example, if the minimum region size is 16 kilobytes (KB), regions can be located at addresses such as 0x0, 0x4000, 0x8000, ... .

Equation 1. Base Address Computation

BASE = <base address>/<min_region>

For example, if the region starts at 0x1000 and the minimum region size is 256 bytes, set the BASE field to 0x10, which is 0x1000/256.

The INDEX field provides a unique identifier for the region. INDEX also specifies the priority of the region. The lower the index value, the higher the region’s priority.

Use the D field to specify the region type: data or instruction.

Register mpuacc Usage

mpuacc has two possible layouts, depending on the Platform Designer generation-time option Use limit for region range, as described in Adding the MPU Hardware section. This option controls whether the mpuacc register contains a MASK or LIMIT field. The table below shows the layout of the mpuacc register with the MASK field.

Table 20.  mpuacc Control Register Fields for MASK Variation
Bit Fields
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
MASK[n-1:p]4
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
MASK[n-1:p]4 0 MT PERM RD WR
Table 21.  mpuacc Control Register Fields for LIMIT Variation
Bit Fields
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
LIMIT[n:p]4
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
LIMIT[n:p]4 0 MT PERM RD WR
Table 22.  mpuacc Control Register Field Descriptions
Field Description Access Reset Available
MASK MASK specifies the size of the region. Read/Write 0 Only with MPU
LIMIT LIMIT specifies the upper address limit of the region. Read/Write 0 Only with MPU
MT (MT) Memory Type:
  • 0 = peripheral (non-cacheable, non-write bufferable)
  • 1 = normal (cacheable, write bufferable)
  • 2 = device (non-cacheable, write bufferable)
  • 3 = reserved
 Read/Write 0 Only with MPU
PERM PERM specifies the access permissions for the region. Read/Write 0 Only with MPU
RD RD is the read region flag. When RD = 1, wrctl instructions to the mpuacc register perform a read operation. Write 0 Only with MPU
WR WR is the write region flag. When WR = 1, wrctl instructions to the mpuacc register perform a write operation. Write 0 Only with MPU

If the mpuacc register is configured with the MASK field, the MASK field represents the size of your region. The value of MASK is defined in the equation below.

Equation 2. Computing Region Mask

MASK = 0xFFFFFF << log2 ( <region_size> >> 8 )

The table below lists every possible MASK value for an MPU configured with a256-byte minimum region size.

Table 23.  MASK Region Size Encodings
MASK Encoding Region Size
0xFFFFFF 256 bytes
0xFFFFFE 512 bytes
0xFFFFFC 1 KB
0xFFFFF8 2 KB
0xFFFFF0 4 KB
0xFFFFE0 8 KB
0xFFFFC0 16 KB
0xFFFF80 32 KB
0xFFFF00 64 KB
0xFFFE00 128 KB
0xFFFC00 256 KB
0xFFF800 512 KB
0xFFF000 1 MB
0xFFE000 2 MB
0xFFC000 4 MB
0xFF8000 8 MB
0xFF0000 16 MB
0xFE0000 32 MB
0xFC0000 64 MB
0xF80000 128 MB
0xF00000 256 MB
0xE00000 512 MB
0xC00000 1 GB
0x800000 2 GB
0x000000 4 GB

If the mpuacc register is configured with the LIMIT field, LIMIT represents the address immediately following the upper end of your region. For example, suppose the MPU’s minimum region size is 256 bytes, and you need to set up the following region:

  • The region starts at 0x1000
  • The region ends at 0x1FFF

To set up the desired region, configure mpubase.BASE and mpuacc.LIMIT as shown in the following list:

  • Set mpubase.BASE to 0x10, which is 0x1000/256 or (0x1000 >> 8)
  • Set mpuacc.LIMIT to 0x20, which is 0x2000/256 or (0x2000 >> 8)

Use the C field to specify whether a data region is to be cached. Usually, you set C for memory regions and clear it for regions representing registers or general-purpose memory-mapped I/O.

The PERM field defines the permissions for the region, as shown in the two tables below.

Table 24.  Instruction Region Permission Encodings
PERM Encoding Supervisor Permissions User Permissions
000 None None
001 Execute None
010 Execute Execute
Table 25.  Data Region Permission Encodings
PERM Encoding Supervisor Permissions User Permissions
000 None None
001 Read None
010 Read Read
100 Read/Write None
101 Read/Write Read
110 Read/Write Read/Write

Defining Regions with mpubase and mpuacc

The mpubase register works in conjunction with the mpuacc register to set and retrieve MPU region information. Use the RD and WR fields of mpuacc to instruct the MPU to perform an MPU region read or write, as shown in the following list:

  • Set mpuacc.RD = 1 to perform an MPU region read operation.
  • Set mpuacc.WR = 1 to perform an MPU region write operation.
Note: Simultaneously setting both the RD and WR fields to 1 results in undefined behavior.

An MPU region must be disabled if it is not in use. To disable a region, software sets up the following conditions:

  • mpubase.BASE is any nonzero value.
  • If the MPU is configured to define region size by mask, mpuacc.MASK represents 0x100000000, which is 232 (the size of the Nios® II address space). For example, if the minimum region size is 256, or 0x100 bytes, mpuacc.MASK is 0x100000000 / 0x100, or 0x10000000.
  • If the MPU is configured to define region size by limit, mpuacc.LIMIT = 0.
2 This field size is variable. Unused upper bits must be written as zero.
3 This field size is variable. Unused upper bits and unused lower bits must be written as zero.
4 This field size is variable. Unused upper bits and unused lower bits must be written as zero.
Level Two Title