Guidelines for Developing a Nios II HAL Device Driver

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ID 683146
Date 6/12/2015
Public
Document Table of Contents
Document Table of Contents x
1. Guidelines for Developing a Nios II HAL Device Driver
1. Guidelines for Developing a Nios II HAL Device Driver x
1.1. Prerequisites for HAL Device Driver Development 1.2. Developing the HAL UART Device Driver 1.3. Debugging the bit_bang_uart Project 1.4. The BitBangUartTransmit() Function 1.5. The BitBangUartReceive() Function 1.6. Creating Device Hardware Access Macros 1.7. Staging the HAL Device Driver Development 1.8. Understanding the Hardware-Specific INSTANCE and INIT Macros 1.9. Integrating a New HAL Device Driver in the BSP 1.10. Understanding HAL Mutual Exclusion Resources 1.11. Overview of Debugging Tools for HAL Device Drivers 1.12. Debugging the HAL UART Device Driver 1.13. Conclusion 1.14. Document Revision History
1.1. Prerequisites for HAL Device Driver Development x
1.1.1. Using the HAL Architecture and Services 1.1.2. Software Requirements for the Driver Example 1.1.3. HAL Device Drivers and Components
1.2. Developing the HAL UART Device Driver x
1.2.1. Preparing the bit_bang_uart Application and hal_my_uart BSP 1.2.2. Preparing the my_uart_driver Device Driver 1.2.3. Configuring the Altera_Avalon_UART Component 1.2.4. Importing Projects 1.2.5. Verifying Software Functionality 1.2.6. Preview: Customizing the Design
1.2.6. Preview: Customizing the Design x
1.2.6.1. Making Software Modifications 1.2.6.2. Making Hardware Modifications
1.12. Debugging the HAL UART Device Driver x
1.12.1. Setting Breakpoints in the my_uart_driver Device Driver 1.12.2. Setting Watchpoints in the HAL UART Device Driver 1.12.3. Reducing Driver Code and Memory Footprint 1.12.4. Interrupt Latency and Determinism 1.12.5. Debugging with the Altera Logging Functions
1.12.3. Reducing Driver Code and Memory Footprint x
1.12.3.1. Using the Reduced Device Drivers API Option 1.12.3.2. Using the Lightweight Device Drivers API Option
1.12.5. Debugging with the Altera Logging Functions x
1.12.5.1. Altera Logging Usage 1.12.5.2. Altera Logging Example
1. Guidelines for Developing a Nios II HAL Device Driver

1. Guidelines for Developing a Nios II HAL Device Driver

This application note explains the process of creating and debugging a hardware abstraction layer (HAL) software device driver. The included example of a HAL software device driver, called my_uart_driver, illustrates various software development stages. The example driver targets the Altera_Avalon_UART device, connected through a Vectored Interrupt Controller (VIC) to the Nios® II processor.

This application note helps you with custom device driver development for Nios II systems in the following ways:

  • Shows the development process steps, from sending bits out the transmit pin in the main() through the construction of device access macros and automatic device initialization in alt_sys_init()
  • Shows how to develop a driver with the command-line based Nios II Software Build Tools (SBT)
  • Shows how to create applications and a board support package (BSP) based on your driver
  • Shows how to import and debug the applications and BSP with the Nios II Software Build Tools for Eclipse
  • Explains interrupt latency, interrupt nesting, and determinism
  • Identifies system calls that cannot be included in a device driver interrupt service routine (ISR)
  • Describes debugging tips and techniques, such as identifying UART transmission errors
Note: This application note uses the Nios II Gen2, Cyclone® V E FPGA Development Kit, as an example hardware platform.

For more information about the HAL, refer to the "Overview of the Hardware Abstraction Layer" chapter in the Nios II Software Developer's Handbook. For more information about interrupt latency, refer to the "Exception Handling" chapter in the Nios II Software Developer's Handbook.


Section Content
Prerequisites for HAL Device Driver Development
Developing the HAL UART Device Driver
Debugging the bit_bang_uart Project
The BitBangUartTransmit() Function
The BitBangUartReceive() Function
Creating Device Hardware Access Macros
Staging the HAL Device Driver Development
Understanding the Hardware-Specific INSTANCE and INIT Macros
Integrating a New HAL Device Driver in the BSP
Understanding HAL Mutual Exclusion Resources
Overview of Debugging Tools for HAL Device Drivers
Debugging the HAL UART Device Driver
Conclusion
Document Revision History

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