Example Summary

This example shows how to use the Non-Volatile Storage (NVS) driver to read and write data to on-chip flash memory.

Peripherals & Pin Assignments

When this project is built, the SysConfig tool will generate the TI-Driver configurations into the ti_drivers_config.c and ti_drivers_config.h files. Information on pins and resources used is present in both generated files. Additionally, the System Configuration file (*.syscfg) present in the project may be opened with SysConfig's graphical user interface to determine pins and resources used.

• CONFIG_NVSINTERNAL - Non-volatile storage used by a NVS driver instance.

BoosterPacks, Board Resources & Jumper Settings

For board specific jumper settings, resources and BoosterPack modifications, refer to the Board.html file.

If you're using an IDE such as Code Composer Studio (CCS) or IAR, please refer to Board.html in your project directory for resources used and board-specific jumper settings.

The Board.html can also be found in your SDK installation:

    <SDK_INSTALL_DIR>/source/ti/boards/<BOARD>

Example Usage

• Example output is generated through use of Display driver APIs. Refer to the Display driver documentation found in the SimpleLink MCU SDK User's Guide.

• Open a serial session (e.g. PuTTY, etc.) to the appropriate COM port.

• The COM port can be determined via Device Manager in Windows or via ls /dev/tty* in Linux.

The connection will have the following settings:

    Baud-rate:     115200
    Data bits:          8
    Stop bits:          1
    Parity:          None
    Flow Control:    None

• Run the example.

• The example will output the region attributes as defined by CONFIG_NVSINTERNAL.

• The example checks if the string, "SimpleLink SDK Non-Volatile Storage (NVS) Example" is present in non-volatile storage.

  • If present, the string is displayed to the UART console. The entire flash sector is then erased.
  • If not present, the string is written to the non-volatile storage.

• Disconnect the device from the debug session.

• When prompted, reset the device. This will cause the application to start over.

• The region base address, sector size and region size will vary depending on the device specific definitions in the board file.

• NOTE FOR GCC: Sysconfig is not able to place the NVS region at the address specified by the "Region Base" configuration parameter (0x10000 in this example). If your application requires the NVS region to begin at a specific location, the linker script must be modified to explicitly place the .nvs section at the desired address. For example to place the .nvs section at 0x10000, the .nvs section should look as follows:

    SECTIONS: {

    ...

        .nvs 0x10000 (NOLOAD) : ALIGN(0x2000) {
            *(.nvs)
        } > REGION_TEXT

    ...

    }

The following is example output assuming the string was not present in non-volatile storage:

    Region Base Address: 0x1B000
    Sector Size: 0x1000
    Region Size: 0x4000

    Writing signature to flash...
    Reset the device.
    ==================================================

The following is example output assuming the string is present in non-volatile storage:

    Region Base Address: 0x1B000
    Sector Size: 0x1000
    Region Size: 0x4000

    SimpleLink SDK Non-Volatile Storage (NVS) Example.
    Erasing flash sector...
    Reset the device.
    ==================================================

Application Design Details

• The application utilizes a single thread to demonstrate using the non-volatile storage region defined by CONFIG_NVSINTERNAL.

• CONFIG_NVSINTERNAL defines a non-volatile storage located on the device's on-chip internal flash memory. The memory definitions may be found in the board file. After NVS_open(), the nvsHandle is associated with the memory region defined by CONFIG_NVSINTERNAL.

• A block of memory the size of signature bytes is read from flash and copied into RAM (buffer). An offset of 0 is used with the NVS_read() call. The NVS memory location read is therefore equal to the NVS region base address, NVS_Attrs.baseAddress. The contents copied into buffer are compared to signature.

  • If equal, the application displays the signature to the UART console. It is important to note that the string was copied into RAM (buffer) during NVS_read(). This example chooses to display the string directly from the NVS region in flash. After the string is output to the UART console, the first sector in the NVS region is erased.
  • If not equal, the application writes the string, signature to the NVS region. An offset of 0 is specified with the NVS_write call. The NVS memory location written to is therefore equal to the NVS region base address, NVS_Attrs.baseAddress.

• At the end of execution, the application prompts the user to reset the device. Upon a reset, the contents of volatile memory (RAM) are lost. The example application restarts.

• The NVS_WRITE_ERASE flag is used with the NVS_write() API to ensure the flash sector is erased prior to performing a write. This flag will erase NVS_Attrs.sectorSize bytes of memory starting at the offset specified with NVS_write().

• The NVS_WRITE_POST_VERIFY flag is also used with the NVS_write() API to ensure the flash memory was successfully written.

TI-RTOS:

• When building in Code Composer Studio, the kernel configuration project will be imported along with the example. The kernel configuration project is referenced by the example, so it will be built first. The "release" kernel configuration is the default project used. It has many debug features disabled. These feature include assert checking, logging and runtime stack checks. For a detailed difference between the "release" and "debug" kernel configurations and how to switch between them, please refer to the SimpleLink MCU SDK User's Guide. The "release" and "debug" kernel configuration projects can be found under <SDK_INSTALL_DIR>/kernel/tirtos/builds/<BOARD>/(release|debug)/(ccs|gcc).

FreeRTOS:

• Please view the FreeRTOSConfig.h header file for example configuration information.