NVSMSP432.h File Reference

#include <stdint.h>
#include <stdbool.h>

Go to the source code of this file.

Data Structures
struct	NVSMSP432_HWAttrs
	NVSMSP432 attributes. More...
struct	NVSMSP432_Object

Typedefs
typedef struct NVSMSP432_HWAttrs	NVSMSP432_HWAttrs
	NVSMSP432 attributes. More...
typedef struct NVSMSP432_Object	NVSMSP432_Object

Functions
void	NVSMSP432_close (NVS_Handle handle)
int_fast16_t	NVSMSP432_control (NVS_Handle handle, uint_fast16_t cmd, uintptr_t arg)
int_fast16_t	NVSMSP432_erase (NVS_Handle handle, size_t offset, size_t size)
void	NVSMSP432_getAttrs (NVS_Handle handle, NVS_Attrs *attrs)
void	NVSMSP432_init ()
int_fast16_t	NVSMSP432_lock (NVS_Handle handle, uint32_t timeout)
NVS_Handle	NVSMSP432_open (uint_least8_t index, NVS_Params *params)
int_fast16_t	NVSMSP432_read (NVS_Handle handle, size_t offset, void *buffer, size_t bufferSize)
void	NVSMSP432_unlock (NVS_Handle handle)
int_fast16_t	NVSMSP432_write (NVS_Handle handle, size_t offset, void *buffer, size_t bufferSize, uint_fast16_t flags)

Variables
const NVS_FxnTable	NVSMSP432_fxnTable
	NVS function pointer table. More...

Typedef Documentation

NVSMSP432_HWAttrs

typedef struct NVSMSP432_HWAttrs NVSMSP432_HWAttrs

NVSMSP432 attributes.

The 'regionBase' field must point to the base address of the region to be managed.

The regionSize must be an integer multiple of the flash sector size. For most MSP432 devices, the flash sector size is 4096 bytes. The NVSMSP432 driver will determine the device's actual sector size by reading internal system configuration registers.

Care must be taken to ensure that the linker does not unintentionally place application content (e.g., code/data) in the flash regions.

For CCS and IAR tools, defining and reserving flash memory regions can be done entirely within the Board.c file. For GCC, additional content is required in the application's linker command file to achieve the same result.

The example below defines a char array, 'flashBuf' and uses compiler CCS and IAR compiler pragmas to place 'flashBuf' at a specific address within the flash memory.

For GCC, the 'flashBuf' array is placed into a named linker section. Corresponding linker commands are added to the application's linker command file to place the section at a specific flash memory address. The section placement command is carefully chosen to only RESERVE space for the 'flashBuf' array, and not to actually initialize it during the application load process, thus preserving the content of flash.

The 'regionBase' fields of the two HWAttrs region instances are initialized to point to the base address of 'flashBuf' and to some offset from the base of the char array.

The linker command syntax is carefully chosen to only RESERVE space for the char array and not to actually initialize it during application load.

#define SECTORSIZE 0x1000
#define FLASH_REGION_BASE 0x3b000

//
// Reserve flash sectors for NVS driver use
// by placing an uninitialized byte array
// at the desired flash address.
//
#if defined(__TI_COMPILER_VERSION__)

//
//  Place uninitialized array at FLASH_REGION_BASE
//
#pragma LOCATION(flashBuf, FLASH_REGION_BASE);
#pragma NOINIT(flashBuf);
char flashBuf[SECTORSIZE * 4];

#elif defined(__IAR_SYSTEMS_ICC__)

//
//  Place uninitialized array at FLASH_REGION_BASE
//
__no_init char flashBuf[SECTORSIZE * 4] @ FLASH_REGION_BASE;

#elif defined(__GNUC__)

//
//  Place the reserved flash buffers in the .nvs section.
//  The ,nvs section will be placed at address FLASH_REGION_BASE by
//  the gcc linker cmd file.
//
__attribute__ ((section (".nvs")))
char flashBuf[SECTORSIZE * 4];

#endif

NVSMSP432_HWAttrs nvsMSP432HWAttrs[2] = {
    //
    // region 0 is 1 flash sector in length.
    //
    {
        .regionBase = (void *)flashBuf,
        .regionSize = SECTORSIZE,
    },
    //
    // region 1 is 3 flash sectors in length.
    //
    {
        .regionBase = (void *)(flashBuf + SECTORSIZE),
        .regionSize = SECTORSIZE*3,
    }
};

Example GCC linker command file content reserves flash space
but does not initialize it:

MEMORY
{
    MAIN_FLASH (RX) : ORIGIN = 0x00000000, LENGTH = 0x00040000
    INFO_FLASH (RX) : ORIGIN = 0x00200000, LENGTH = 0x00004000
    SRAM_CODE  (RWX): ORIGIN = 0x01000000, LENGTH = 0x00010000
    SRAM_DATA  (RW) : ORIGIN = 0x20000000, LENGTH = 0x00010000
}

.nvs (0x3b000) (NOLOAD) : AT (0x3b000) {
    KEEP (*(.nvs))
} > NVS

NVSMSP432_Object

typedef struct NVSMSP432_Object NVSMSP432_Object

Function Documentation

NVSMSP432_close()

void NVSMSP432_close

(

NVS_Handle

handle

)

NVSMSP432_control()

int_fast16_t NVSMSP432_control	(	NVS_Handle	handle,
		uint_fast16_t	cmd,
		uintptr_t	arg
	)

NVSMSP432_erase()

int_fast16_t NVSMSP432_erase	(	NVS_Handle	handle,
		size_t	offset,
		size_t	size
	)

NVSMSP432_getAttrs()

void NVSMSP432_getAttrs	(	NVS_Handle	handle,
		NVS_Attrs *	attrs
	)

NVSMSP432_init()

void NVSMSP432_init

(

)

NVSMSP432_lock()

int_fast16_t NVSMSP432_lock	(	NVS_Handle	handle,
		uint32_t	timeout
	)

NVSMSP432_open()

NVS_Handle NVSMSP432_open	(	uint_least8_t	index,
		NVS_Params *	params
	)

NVSMSP432_read()

int_fast16_t NVSMSP432_read	(	NVS_Handle	handle,
		size_t	offset,
		void *	buffer,
		size_t	bufferSize
	)

NVSMSP432_unlock()

void NVSMSP432_unlock

(

NVS_Handle

handle

)

NVSMSP432_write()

int_fast16_t NVSMSP432_write	(	NVS_Handle	handle,
		size_t	offset,
		void *	buffer,
		size_t	bufferSize,
		uint_fast16_t	flags
	)

Variable Documentation

NVSMSP432_fxnTable

const NVS_FxnTable NVSMSP432_fxnTable

NVS function pointer table.

'NVSMSP432_fxnTable' is a fully populated function pointer table that can be referenced in the NVS_config[] array entries.

Users can minimize their application code size by providing their own custom NVS function pointer table that contains only those APIs used by the application.

An example of a custom NVS function table is shown below:

//
// Since the application does not use the
// NVS_control(), NVS_lock(), and NVS_unlock() APIs,
// these APIs are removed from the function
// pointer table and replaced with NULL
//
const NVS_FxnTable myNVS_fxnTable = {
    NVSMSP432_close,
    NULL,     // remove NVSMSP432_control(),
    NVSMSP432_erase,
    NVSMSP432_getAttrs,
    NVSMSP432_init,
    NULL,     // remove NVSMSP432_lock(),
    NVSMSP432_open,
    NVSMSP432_read,
    NULL,     // remove NVSMSP432_unlock(),
    NVSMSP432_write
};