Detailed Description

NVM3 Non-Volatile Memory Management driver.

Note: Quality Announcement - This driver is Beta tested only. Silicon Labs will NOT support any production deployments with this Beta release. Production deployments will only be supported with the GA version of NVM3. This version is intended for lab and evaluation purpose only.

Introduction

The NVM3 driver provides a way for an application to safely store and retrieve variable size objects in a page based non-volatile memory. Objects are identified with 20-bit object identifiers denoted as keys.

The driver is designed to use pages in a sequential order to provide equal usage and wear. The driver is resilient to power loss or reset events, ensuring that objects retrieved from the driver are in a valid state. A valid object will always be the last successfully stored object. NVM3 can detect NVM defects and mark pages as unusable. NVM3 will continue to operate on good pages after defect pages are detected.

Objects

A NVM3 object is a piece of data that can be stored in NVM. The object is handled as an array of bytes up to NVM3_MAX_OBJECT_SIZE in size. NVM3 can handle two types of objects.

Regular data objects. Data objects can store information of any size up to maximum NVM3_MAX_OBJECT_SIZE bytes.
32-bit counter objects. Counter objects can store 32-bit counters that are accessed with a separate set of API functions. The counter object is designed to be compact while minimizing memory wear in applications that require frequent persistent counter increments.

See The API for more details on the API.

Repacking

As the NVM fills up, there will be a point where it can no longer store additional objects. A repacking operation is required to release out-of-date objects to free up NVM. Because erasing pages takes a long time, the NVM3 driver does not trigger the process by itself unless free memory reaches a critical low level. Instead, the application must trigger the repacking process by calling the nvm3_repack() function. During the call, the NVM3 will either move data to a new page or erase an obsolete page. At most, the call will block for a period equal to a page erasure time plus a small execution overhead. Page erasure time for the EFM32 or EFR32 parts can be found in the data sheet.

The application can also use nvm3_repackNeeded() to determine when to execute repacking. The function nvm3_repack() will only perform a repack operation if needed.

Note: Any NVM3 function that modifies a data or counter object may trigger an automatic repacking operation if free memory has reached a critical low level.

NVM3 uses two internal thresholds for repacking:

Soft low memory threshold. This is the threshold used by nvm3_repackNeeded() . The soft threshold is set to reduce memory wear to a minimum. nvm3_repack() will not perform repacking unless free memory is below this threshold.
Hard low memory threshold. This is the threshold used to force repacking when free memory reaches a critical low level.

Soft and hard low memory thresholds are not configurable.

Caching

Caching is an optional feature. The NVM3 cache is an object location lookup cache, data is not stored in the cache. Using the cache will speed up accesses to the NVM3, and the performance will very much depend on objects beeing available in the cache. To ensure that the cache can hold all neccesary information, it must be configured to a size equivalent or larger than the number of objects stored in NVM. If the cache is available, the driver will first look in the cache to find the position of the object in NVM. If the object position is not found in the cache, the object position will be found by searching the NVM. The search will start at the last stored object and search all the way to the oldest object. If the object is found, the cache is updated accordingly.

It is the application that must allocate and support the data for the cache, see the nvm3_open function for more details.

Note: The cache is fully initialized by nvm3_open() and automatically updated by any subsequent write, read, or delete function call.

The API

This section contains brief descriptions of the API functions. For more information about parameters and return values see the Function Documentation section. Most functions return an Ecode_t that has the value ECODE_NVM3_OK on success or see nvm3.h for other values.

The application code must include the nvm3.h header file.

nvm3_open() and nvm3_close() .
Functions to open and close an NVM3 instance. nvm3_open() takes a handle of type nvm3_Handle_t and initialization data of type nvm3_Init_t . The helper macro pair NVM3_DEFINE_SECTION_STATIC_DATA() and NVM3_DEFINE_SECTION_INIT_DATA() are provided to simplify initialization data definition. For usage examples, see the Examples section.

nvm3_findObject() , nvm3_enumObjects() , nvm3_deleteObject() and nvm3_countObjects()
Functions for regular objects. nvm3_enumObjects() provides a way to get a list of keys to valid objects in the NVM. The search can also be constrained. nvm3_countObjects() can be useful at startup to distinguish between a first startup without any valid objects present and later reboots with valid objects persistently stored in NVM.

nvm3_writeData() and nvm3_readData()
Functions to write and read data objects.

nvm3_writeCounter() , nvm3_readCounter() and nvm3_incrementCounter()
Functions to write, increment, and read 32-bit counter objects.

nvm3_eraseAll()
Erase all objects in NVM.

nvm3_getEraseCount()
Return the erasure count for the most erased page in NVM.

nvm3_repack() and nvm3_repackNeeded()
Manage NVM3 repacking operation.

Memory Placement

The application is responsible for placing the NVM area correctly. Minimum requirements for memory placement are:

NVM area start address must be aligned with the page size of the underlying memory system.
NVM area size must be a multiple of the page size.
Minimim required NVM area size:
- For page size of 1kB: 10 pages
- For page size of 2kB: 6 pages
- For page size of 4kB: 4 pages

Two macros are provided to support the creation of the NVM area and initialization data; NVM3_DEFINE_SECTION_STATIC_DATA() and NVM3_DEFINE_SECTION_INIT_DATA() . A linker section called 'name'_section is defined by NVM3_DEFINE_SECTION_STATIC_DATA() . The NVM area is placed within the linker section. The application linker script must place the section according to the requirements above. An error is returned by nvm3_open() on alignment or size violation.

Configuration Options

There are no compile-time configuration options for NVM3. All configuration parameters are contained in nvm3_Init_t .

Examples

Example 1 shows initialization, usage of data objects and repacking.

       
        #include "
        
         nvm3.h
        
        "
       
        // Create a NVM area across 6 Flash pages. Create a cache of 10 entries.
       
        NVM3_DEFINE_SECTION_STATIC_DATA
       
       (nvm3Data1, 6 *
       
        FLASH_PAGE_SIZE
       
       , 10);
      
        // This macro creates the following:
       
        // 1. An array to hold NVM data named nvm3Data1_nvm
       
        // 2. A section called nvm3Data1_section containing nvm3Data1_nvm. The application linker script must place this section correctly in memory.
       
        // 3. A cache array: nvm3Data1_cache
       
        void
       
       nvm3_example_1(
       
        void
       
       )
      
       {
      
        // Declare a nvm3_Init_t struct of name nvm3Data1 with initialization data. This is passed to nvm3_open() below.
       
        NVM3_DEFINE_SECTION_INIT_DATA
       
       (nvm3Data1);
      
       nvm3_Handle_t handle;
      
        Ecode_t
       
       status;
      
        size_t
       
       numberOfObjects;
      
        unsigned
       
        char
       
       data1[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
      
        unsigned
       
        char
       
       data2[] = { 11, 12, 13, 14, 15 };
      
       nvm3_ObjectType_t objectType;
      
        size_t
       
       dataLen1;
      
        size_t
       
       dataLen2;
      
       status =
       
        nvm3_open
       
       (&handle, &nvm3Data1);
      
        if
       
       (status !=
       
        ECODE_NVM3_OK
       
       ) {
      
        // Handle error
       
       }
      
        // Get the number of valid keys already in NVM3
       
       numberOfObjects =
       
        nvm3_countObjects
       
       (&handle);
      
        // Skip if we have initial keys. If not, generate objects and store
       
        // persistently in NVM3 before proceeding.
       
        if
       
       (numberOfObjects < 2) {
      
        // Erase all objects and write initial data to NVM3
       
        nvm3_eraseAll
       
       (&handle);
      
        nvm3_writeData
       
       (&handle, 1, data1,
       
        sizeof
       
       (data1));
      
        nvm3_writeData
       
       (&handle, 2, data2,
       
        sizeof
       
       (data2));
      
       }
      
        // Find size of data for object with key identifier 1 and 2 and read out
       
        nvm3_findObject
       
       (&handle, 1, &objectType, &dataLen1);
      
        if
       
       (objectType == nvm3_objectTypeData) {
      
        nvm3_readData
       
       (&handle, 1, data1, dataLen1);
      
       }
      
        nvm3_findObject
       
       (&handle, 2, &objectType, &dataLen2);
      
        if
       
       (objectType == nvm3_objectTypeData) {
      
        nvm3_readData
       
       (&handle, 2, data2, dataLen2);
      
       }
      
        // Update and write back data
       
       data1[0]++;
      
       data2[0]++;
      
        nvm3_writeData
       
       (&handle, 1, data1, dataLen1);
      
        nvm3_writeData
       
       (&handle, 2, data2, dataLen2);
      
        // Do repacking if needed
       
        if
       
       (
       
        nvm3_repackNeeded
       
       (&handle)) {
      
       status =
       
        nvm3_repack
       
       (&handle);
      
        if
       
       (status !=
       
        ECODE_NVM3_OK
       
       ) {
      
        // Handle error
       
       }
      
       }
      
       }

Example 2 shows initialization and usage of counter objects. The counter object uses a compact way of storing a 32-bit counter value while minimizing NVM wear.

       
        #include "
        
         nvm3.h
        
        "
       
        // Create a NVM area across 6 Flash pages. Create a cache of 10 entries.
       
        NVM3_DEFINE_SECTION_STATIC_DATA
       
       (nvm3Data2, 6 *
       
        FLASH_PAGE_SIZE
       
       , 10);
      
        #define USER_KEY 1
       
        // This macro creates the following:
       
        // 1. An array to hold NVM data named nvm3Data2_nvm
       
        // 2. A section called nvm3Data2_section containing nvm3Data2_nvm. The application linker script must place this section correctly in memory.
       
        // 3. A cache array: nvm3Data2_cache
       
        void
       
       nvm3_example_2(
       
        void
       
       )
      
       {
      
        // Declare a nvm3_Init_t struct of name nvm3Data2 with initialization data. This is passed to nvm3_open() below.
       
        NVM3_DEFINE_SECTION_INIT_DATA
       
       (nvm3Data2);
      
       nvm3_Handle_t handle;
      
        Ecode_t
       
       status;
      
       uint32_t counter = 1;
      
       status =
       
        nvm3_open
       
       (&handle, &nvm3Data2);
      
        if
       
       (status !=
       
        ECODE_NVM3_OK
       
       ) {
      
        // Handle error
       
       }
      
        // Erase all objects
       
        nvm3_eraseAll
       
       (&handle);
      
        // Write first counter value with key 1
       
        nvm3_writeCounter
       
       (&handle, USER_KEY, counter);
      
        // Increment the counter by 1 without reading out the updated value
       
        nvm3_incrementCounter
       
       (&handle, USER_KEY, NULL);
      
        // Read the counter value
       
        nvm3_readCounter
       
       (&handle, USER_KEY, &counter);
      
       }

Modules
NVM3Hal
NVM3 hal module.

NVM3Lock
NVM3 lock module.

Data Structures
struct	nvm3_CacheEntry
	The datatype for each cache entry. The cache must be an array of these.

struct	nvm3_Init_t
	NVM3 initialization data.

Macros
#define	ECODE_NVM3_ERR_ALIGNMENT_INVALID ( ECODE_EMDRV_NVM3_BASE \| 0x00000001U)
	Invalid data alignment.

#define	ECODE_NVM3_ERR_ERASE_FAILED ( ECODE_EMDRV_NVM3_BASE \| 0x0000000EU)
	Erase failed.

#define	ECODE_NVM3_ERR_INT_ADDR_INVALID ( ECODE_EMDRV_NVM3_BASE \| 0x00000021U)
	Internal error trying to access invalid memory.

#define	ECODE_NVM3_ERR_INT_EMULATOR ( ECODE_EMDRV_NVM3_BASE \| 0x00000024U)
	Internal Emulator error.

#define	ECODE_NVM3_ERR_INT_KEY_MISMATCH ( ECODE_EMDRV_NVM3_BASE \| 0x00000022U)
	Key validaton failure.

#define	ECODE_NVM3_ERR_INT_SIZE_ERROR ( ECODE_EMDRV_NVM3_BASE \| 0x00000023U)
	Internal size mismatch error.

#define	ECODE_NVM3_ERR_INT_TEST ( ECODE_EMDRV_NVM3_BASE \| 0x00000025U)
	Internal Test error.

#define	ECODE_NVM3_ERR_INT_WRITE_TO_NOT_ERASED ( ECODE_EMDRV_NVM3_BASE \| 0x00000020U)
	Write to memory that is not erased.

#define	ECODE_NVM3_ERR_KEY_INVALID ( ECODE_EMDRV_NVM3_BASE \| 0x0000000AU)
	Invalid key ID.

#define	ECODE_NVM3_ERR_KEY_NOT_FOUND ( ECODE_EMDRV_NVM3_BASE \| 0x0000000BU)
	Error, key not found.

#define	ECODE_NVM3_ERR_NO_VALID_PAGES ( ECODE_EMDRV_NVM3_BASE \| 0x00000003U)
	Initialisation aborded, no valid page found.

#define	ECODE_NVM3_ERR_NOT_OPENED ( ECODE_EMDRV_NVM3_BASE \| 0x00000007U)
	The module has not been sucessfully opened.

#define	ECODE_NVM3_ERR_OBJECT_IS_NOT_A_COUNTER ( ECODE_EMDRV_NVM3_BASE \| 0x0000000DU)
	Trying to access a counter object which is currently a data object.

#define	ECODE_NVM3_ERR_OBJECT_IS_NOT_DATA ( ECODE_EMDRV_NVM3_BASE \| 0x0000000CU)
	Trying to access a data object which is currently a counter object.

#define	ECODE_NVM3_ERR_OBJECT_SIZE_NOT_SUPPORTED ( ECODE_EMDRV_NVM3_BASE \| 0x00000005U)
	The object size is not supported.

#define	ECODE_NVM3_ERR_OPENED_WITH_OTHER_PARAMETERS ( ECODE_EMDRV_NVM3_BASE \| 0x00000008U)
	The module has already been opened with other parameters.

#define	ECODE_NVM3_ERR_PAGE_SIZE_NOT_SUPPORTED ( ECODE_EMDRV_NVM3_BASE \| 0x00000004U)
	The page size is not supported.

#define	ECODE_NVM3_ERR_PARAMETER ( ECODE_EMDRV_NVM3_BASE \| 0x00000009U)
	Error in parameter.

#define	ECODE_NVM3_ERR_READ_COUNTER_SIZE ( ECODE_EMDRV_NVM3_BASE \| 0x00000012U)
	Trying to read a counter with length different from 4.

#define	ECODE_NVM3_ERR_READ_DATA_SIZE ( ECODE_EMDRV_NVM3_BASE \| 0x00000011U)
	Trying to read more than the actual object size.

#define	ECODE_NVM3_ERR_SIZE_TOO_SMALL ( ECODE_EMDRV_NVM3_BASE \| 0x00000002U)
	Not enough nvm memory specified.

#define	ECODE_NVM3_ERR_STORAGE_FULL ( ECODE_EMDRV_NVM3_BASE \| 0x00000006U)
	No more space available.

#define	ECODE_NVM3_ERR_WRITE_DATA_SIZE ( ECODE_EMDRV_NVM3_BASE \| 0x0000000FU)
	The object is too large.

#define	ECODE_NVM3_ERR_WRITE_FAILED ( ECODE_EMDRV_NVM3_BASE \| 0x00000010U)
	Error, error during the write operation.

#define	ECODE_NVM3_OK ( ECODE_OK )
	Success return value.

#define	NVM3_DEFAULT_MAX_OBJECT_SIZE NVM3_MAX_OBJECT_SIZE
	The default max object size.

#define	NVM3_DEFINE_SECTION_INIT_DATA (name)
	NVM3 initialization data helper macro to be used with NVM3_DEFINE_SECTION_STATIC_DATA() . The `name` parameter in both macros must match. Call nvm3_open() after this macro to initialize NVM3. See Examples section for code examples.

#define	NVM3_DEFINE_SECTION_STATIC_DATA (name, nvmSize, cacheSize)
	NVM3 static data definition helper macro for applications using linker script placement of NVM memory area. This macro exports the section 'name'_section to the linker. The section name must be placed by the user in a linker script at an address aligned with the page size of the underlying memory system. The size of the NVM area must be a multiple of the page size. This macro also allocates static NVM3 cache. Use this macro with NVM3_DEFINE_SECTION_INIT_DATA() to create initialization data for nvm3_open() . See Examples section for usage examples.

#define	NVM3_KEY_INVALID 0xFFFFFFFFU
	Invalid key identifier.

#define	NVM3_KEY_MASK ((1U << NVM3_KEY_SIZE) - 1U)
	Unique object key identifier mask.

#define	NVM3_KEY_MAX NVM3_KEY_MASK
	Maximum object key value.

#define	NVM3_KEY_MIN 0U
	Minimum object key value.

#define	NVM3_KEY_SIZE 20U
	Unique object key identifier size.

#define	NVM3_MAX_OBJECT_SIZE 4096U
	NVM3 default maximum object size. Because the current NVM3 version only supports the maximum object size equal to NVM3_MAX_OBJECT_SIZE, this macro can be used to set the maxObjectSize in the initialization structure. Future versions of NVM3 may support other sizes.

#define	NVM3_OBJECTTYPE_COUNTER 1U
	The object is a counter.

#define	NVM3_OBJECTTYPE_DATA 0U
	The object is data.

Typedefs
typedef struct nvm3_CacheEntry	nvm3_CacheEntry_t
	The datatype for each cache entry. The cache must be an array of these.

typedef uint32_t	nvm3_ObjectKey_t
	The data type for object keys. Only the 20 least significant bits are used.

Functions
Ecode_t	nvm3_close (nvm3_Handle_t *h)
	Close the NVM3 driver instance.

__STATIC_INLINE size_t	nvm3_countObjects (nvm3_Handle_t *h)
	Count valid objects.

Ecode_t	nvm3_deleteObject (nvm3_Handle_t *h, nvm3_ObjectKey_t key)
	Delete an object from NVM.

size_t	nvm3_enumObjects (nvm3_Handle_t h, nvm3_ObjectKey_t keys, size_t sizeKeys, nvm3_ObjectKey_t keyMin, nvm3_ObjectKey_t keyMax)
	Create a list of object keys for valid objects in NVM.

Ecode_t	nvm3_eraseAll (nvm3_Handle_t *h)
	Delete all objects in NVM.

Ecode_t	nvm3_findObject (nvm3_Handle_t h, nvm3_ObjectKey_t key, uint32_t type, size_t *len)
	Find the type and size of an object in NVM.

Ecode_t	nvm3_getEraseCount (nvm3_Handle_t h, uint32_t eraseCnt)
	Get the number of page erases of the most erased page in the NVM area since the first initialization.

Ecode_t	nvm3_incrementCounter (nvm3_Handle_t h, nvm3_ObjectKey_t key, uint32_t value)
	Increment a counter object value by 1 and read out optionally.

Ecode_t	nvm3_open (nvm3_Handle_t h, const nvm3_Init_t i)
	Open a NVM3 driver instance. A NVM3 instance is represented by a handle keeping information about the state. A successful open will initialize the cache with information about the objects already in the NVM-memory.

Ecode_t	nvm3_readCounter (nvm3_Handle_t h, nvm3_ObjectKey_t key, uint32_t value)
	Read a counter value from NVM.

Ecode_t	nvm3_readData (nvm3_Handle_t h, nvm3_ObjectKey_t key, void value, size_t maxLen)
	Read the object data identified with a given key from NVM.

Ecode_t	nvm3_repack (nvm3_Handle_t *h)
	Execute a repack operation. NVM3 will copy data or erase pages when repacking is needed. A call to nvm3_repack() may block access to the non-volatile memory for up to one page erasure time plus an small execution overhead. Exact worst-case timing characteristics can be found in the data sheet for the part.

bool	nvm3_repackNeeded (nvm3_Handle_t *h)
	Check the internal status of NVM3 and return true if a repack operation is required. The application must call nvm3_repack() to perform the actual repack operation.

Ecode_t	nvm3_writeCounter (nvm3_Handle_t *h, nvm3_ObjectKey_t key, uint32_t value)
	Store a counter in NVM.

Ecode_t	nvm3_writeData (nvm3_Handle_t h, nvm3_ObjectKey_t key, const void value, size_t len)
	Write the object value identified with the key to NVM.

Macro Definition Documentation

#define NVM3_DEFINE_SECTION_INIT_DATA ( name )

Value:

         
          nvm3_Init_t
         
         name = \
        
         { \
        
         (
         
          nvm3_HalPtr_t
         
         )name##_nvm, \
        
          sizeof
         
         (name##_nvm), \
        
         name##_cache, \
        
         sizeof(name##_cache) /
         
          sizeof
         
         (
         
          nvm3_CacheEntry_t
         
         ), \
        
          NVM3_DEFAULT_MAX_OBJECT_SIZE
         
         , \
        
         }

NVM3 initialization data helper macro to be used with NVM3_DEFINE_SECTION_STATIC_DATA() . The name parameter in both macros must match.
Call nvm3_open() after this macro to initialize NVM3. See Examples section for code examples.

Definition at line 94 of file nvm3.h .

#define NVM3_DEFINE_SECTION_STATIC_DATA	(	`name,`
		`nvmSize,`
		`cacheSize`
	)

Value:

         
          static
         
          nvm3_CacheEntry_t
         
         name##_cache[cacheSize]; \
        
         static
         
          const
         
         uint8_t name##_nvm[nvmSize]
         
          \
         
          SL_ATTRIBUTE_SECTION
         
         (
         
          STRINGIZE
         
         (name##_section))

NVM3 static data definition helper macro for applications using linker script placement of NVM memory area. This macro exports the section 'name'_section to the linker. The section name must be placed by the user in a linker script at an address aligned with the page size of the underlying memory system. The size of the NVM area must be a multiple of the page size.
This macro also allocates static NVM3 cache.
Use this macro with NVM3_DEFINE_SECTION_INIT_DATA() to create initialization data for nvm3_open() . See Examples section for usage examples.

Definition at line 82 of file nvm3.h .

#define NVM3_MAX_OBJECT_SIZE 4096U

NVM3 default maximum object size. Because the current NVM3 version only supports the maximum object size equal to NVM3_MAX_OBJECT_SIZE, this macro can be used to set the maxObjectSize in the initialization structure. Future versions of NVM3 may support other sizes.

Maximum object size

Definition at line 69 of file nvm3.h .

Function Documentation

Ecode_t nvm3_close ( nvm3_Handle_t * h )

Close the NVM3 driver instance.

Parameters

[in] h A pointer to an NVM3 driver handle.

Returns: ECODE_NVM3_OK is always returned.

__STATIC_INLINE size_t nvm3_countObjects ( nvm3_Handle_t * h )

Count valid objects.

Parameters

[in] h A pointer to an NVM3 driver handle.

Returns: The number of valid objects.

Definition at line 452 of file nvm3.h .

References nvm3_enumObjects() , NVM3_KEY_MAX , and NVM3_KEY_MIN .

Ecode_t nvm3_deleteObject	(	nvm3_Handle_t *	`h,`
		nvm3_ObjectKey_t	`key`
	)

Delete an object from NVM.

Parameters

[in]	`h`	A pointer to an NVM3 driver handle.
[in]	`key`	A 20-bit object identifier.

Returns: ECODE_NVM3_OK on success or a NVM3 Ecode_t on failure.

size_t nvm3_enumObjects	(	nvm3_Handle_t *	`h,`
		nvm3_ObjectKey_t *	`keys,`
		size_t	`sizeKeys,`
		nvm3_ObjectKey_t	`keyMin,`
		nvm3_ObjectKey_t	`keyMax`
	)

Create a list of object keys for valid objects in NVM.

Note: The function nvm3_countObjects() is also provided to count the number of valid objects.

Parameters

[in]	`h`	A pointer to an NVM3 driver handle.
[out]	`keys`	A pointer to a buffer for the key list.
[in]	`sizeKeys`	The size of the key list buffer.
[in]	`keyMin`	The lower search key. Set to NVM3_KEY_MIN to match all keys.
[in]	`keyMax`	The upper search key. Set to NVM3_KEY_MAX to match all keys.

Returns: The number of keys written to the key list. This value is less than or equal to sizeKeys .

Referenced by nvm3_countObjects() .

Ecode_t nvm3_eraseAll ( nvm3_Handle_t * h )

Delete all objects in NVM.

Note: It is not necessary to call this function to get NVM3 into an initial valid state.

Warning: Execution time depends on the configured NVM size and may therefore be significant.

Parameters

[in] h A pointer to an NVM3 driver handle.

Returns: ECODE_NVM3_OK on success or a NVM3 Ecode_t on failure.

Ecode_t nvm3_findObject	(	nvm3_Handle_t *	`h,`
		nvm3_ObjectKey_t	`key,`
		uint32_t *	`type,`
		size_t *	`len`
	)

Find the type and size of an object in NVM.

Parameters

[in]	`h`	A pointer to an NVM3 driver handle.
[in]	`key`	A 20-bit object identifier.
[out]	`type`	A pointer to the location where NVM3 shall write the object type. The type can be either NVM3_OBJECTTYPE_DATA or NVM3_OBJECTTYPE_COUNTER .
[out]	`len`	A pointer to the location where NVM3 shall write the object size.

Returns: ECODE_NVM3_OK on success or a NVM3 Ecode_t on failure.

Ecode_t nvm3_getEraseCount	(	nvm3_Handle_t *	`h,`
		uint32_t *	`eraseCnt`
	)

Get the number of page erases of the most erased page in the NVM area since the first initialization.

Note: Except for pages marked as bad, pages will have an erase count equal to the most erased or one less because of the wear levelling algorithm.

Parameters

[in]	`h`	A pointer to an NVM3 driver handle.
[in]	`eraseCnt`	A pointer to the location where the NVM3 shall place the page erasure counter value.

Returns: ECODE_NVM3_OK on success or a NVM3 Ecode_t on failure.

Ecode_t nvm3_incrementCounter	(	nvm3_Handle_t *	`h,`
		nvm3_ObjectKey_t	`key,`
		uint32_t *	`value`
	)

Increment a counter object value by 1 and read out optionally.

Parameters

[in]	`h`	A pointer to an NVM3 driver handle.
[in]	`key`	A 20-bit object identifier.
[out]	`value`	A pointer to the counter readout location. The counter is incremented before the value is written to this location. Set this value to NULL to ignore readout.

Returns: ECODE_NVM3_OK on success or a NVM3 Ecode_t on failure.

Ecode_t nvm3_open	(	nvm3_Handle_t *	`h,`
		const nvm3_Init_t *	`i`
	)

Open a NVM3 driver instance. A NVM3 instance is represented by a handle keeping information about the state. A successful open will initialize the cache with information about the objects already in the NVM-memory.

Note: A new call to the nvm3_open will return ECODE_NVM3_OK as long as the open parameters are identical to the parameters used in previous successfull open calls. Several NVM3 instances using different handles must NOT overlap NVM-memory. If the application wants to change some of the parameters, this can be done by first calling nvm3_close and then nvm3_open again.

Parameters

[out]	`h`	A pointer to an NVM3 driver handle.
[in]	`i`	A pointer to an NVM3 driver initialization data.

Returns: ECODE_NVM3_OK on success and a NVM3 Ecode_t on failure.

Ecode_t nvm3_readCounter	(	nvm3_Handle_t *	`h,`
		nvm3_ObjectKey_t	`key,`
		uint32_t *	`value`
	)

Read a counter value from NVM.

Parameters

[in]	`h`	A pointer to an NVM3 driver handle.
[in]	`key`	A 20-bit object identifier.
[out]	`value`	A pointer to the counter location. The read function will copy the counter value to this location.

Returns: ECODE_NVM3_OK on success or a NVM3 Ecode_t on failure.

Ecode_t nvm3_readData	(	nvm3_Handle_t *	`h,`
		nvm3_ObjectKey_t	`key,`
		void *	`value,`
		size_t	`maxLen`
	)

Read the object data identified with a given key from NVM.

Parameters

[in]	`h`	A pointer to an NVM3 driver handle.
[in]	`key`	A 20-bit object identifier.
[out]	`value`	A pointer to the application data buffer. The read function will copy the data to this location.
[in]	`maxLen`	The maximum object size in number of bytes. The nvm3_findObject() function can be used to find the actual size.

Returns: ECODE_NVM3_OK on success or a NVM3 Ecode_t on failure.

Ecode_t nvm3_repack ( nvm3_Handle_t * h )

Execute a repack operation. NVM3 will copy data or erase pages when repacking is needed. A call to nvm3_repack() may block access to the non-volatile memory for up to one page erasure time plus an small execution overhead. Exact worst-case timing characteristics can be found in the data sheet for the part.

Note: It is not mandatory to call nvm3_repack() because the functions that write data to NVM will trigger a repack if needed. Because a repack operation may be time consuming, the application may want to be in control of when repacking occures by calling this function.

More information about the repack operation can be found in the Repacking section.

Parameters

[in] h Pointer to an NVM3 driver handle.

Returns: ECODE_NVM3_OK on success or a NVM3 Ecode_t on failure.

bool nvm3_repackNeeded ( nvm3_Handle_t * h )

Check the internal status of NVM3 and return true if a repack operation is required. The application must call nvm3_repack() to perform the actual repack operation.

Parameters

[in] h Pointer to NVM3 driver handle.

Returns: true if repacking is needed, false if repacking is not needed.

Ecode_t nvm3_writeCounter	(	nvm3_Handle_t *	`h,`
		nvm3_ObjectKey_t	`key,`
		uint32_t	`value`
	)

Store a counter in NVM.

Parameters

[in]	`h`	A pointer to an NVM3 driver handle.
[in]	`key`	A 20-bit object identifier.
[in]	`value`	The counter value to write.

Returns: ECODE_NVM3_OK on success or a NVM3 Ecode_t on failure.

Ecode_t nvm3_writeData	(	nvm3_Handle_t *	`h,`
		nvm3_ObjectKey_t	`key,`
		const void *	`value,`
		size_t	`len`
	)

Write the object value identified with the key to NVM.

Parameters

[in]	`h`	A pointer to an NVM3 driver handle.
[in]	`key`	A 20-bit object identifier.
[in]	`value`	A pointer to the object data to write.
[in]	`len`	The size of the object data in number of bytes.

Returns: ECODE_NVM3_OK on success or a NVM3 Ecode_t on failure.

NVM3EMDRV

Detailed Description

Introduction

Objects

Repacking

Caching

The API

Memory Placement

Configuration Options

Examples

Modules

Data Structures

Macros

Typedefs

Functions

Macro Definition Documentation

Function Documentation