NVM3 - NVM Data Manager

Description

NVM3 Non-Volatile Memory Data Management driver.

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

An NVM3 object is 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.

  1. Regular data objects. Data objects can store information of any size up to maximum NVM3_MAX_OBJECT_SIZE bytes.
  2. 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up, it reaches a point where it can no longer store additional objects and a repacking operation is required to release out-of-date objects to free up NVM.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. As an alternative, the application can trigger the repacking process by calling the nvm3_repack() function. During the call, NVM3 will either move data to a new page or erase pages that can be reused. 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 use nvm3_repackNeeded() to determine if repacking is needed. To initiate repacks, call nvm3_repack() . Note that this function will perform repacks only if they are needed.

NVM3 uses two thresholds for repacking:

  1. Forced threshold. This is the threshold used to force automatic repacking when free memory reaches a critical low level.
  2. User threshold. This is the threshold used by nvm3_repackNeeded() . nvm3_repack() will not perform repacking unless free memory is below this threshold.

An NVM3 function that deletes or modifies a data or counter object will trigger an automatic repack operation when free memory is below the forced threshold. The check is done before the object is modified, not after.

The user can define the user threshold by entering a value in the repackHeadroom member of the nvm3_Init_t structure used by the nvm3_open() function. The repackHeadroom value defines the difference between the user and forced threshold. The forced threshold is the minimum low memory threshold defined by the page size and maximum object size and cannot be changed by the user. The default value for the repack headroom is 0, meaning that the forced and user thresholds are equal.

Note
The repack threshold can be changed to prevent multiple modifications of objects between user called repacks from causing automatic repacks. Note that "high" values of the repack headroom may cause increased NVM wear from increased number of repacks.

Caching

NVM3 includes an object location lookup cache to speed up object access, as searching through the entire NVM3 contents for an object could otherwise be slow. It is important to note that this cache only stores the location of the object and not the object data itself. To ensure that cache can hold all necessary information, it must be configured to a size equivalent to or larger than the number of objects stored in NVM including those deleted as long as they are not discarded by the repack function. 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.

The application must allocate and support data for the cache. See the nvm3_open function for more details. The size of each cache element is one uint32_t and one pointer giving a total of 8 bytes (2 words) pr. entry for EFM32 and EFR32 devices.

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

Global Data (variables)

The NVM3 library is using global variables to store intermediate data during open, read, write, increment, and delete calls. Because the actual memory configuration is not defined at the time the NVM3 library is built, but rather at the time the user application is built, the size of data structures must be determined by the application configuration. Also, the application must set the value of the nvm3_maxFragmentCount at run-time before any NVM3 functions are called.

NVM3 does not support overlapped calls. If there is any chance that the application can issue overlapped calls, the NVM3 locking mechanism must be present and protect from that.

Note
If the application is using more than one NVM3 instance, the variables will be shared between the instances. Be sure to allocate data that have a size that is large enough for the largest usage.

Stack Usage

NVM3 library function calls are nested several levels deep. The stack usage has been measured on some EFM32 and EFR32 targets with library builds for IAR and armgcc. The maximum stack usage measured was 420 bytes for IAR and 472 bytes for ARM GCC builds. The unit test used to validate the stack usage has a 10% margin and is using a stack limit at 462 bytes for IAR and 520 for ARM GCC. Please note that the actual stack usage is a little different on the Cortex M0 Plus, M3, M4 and M33 versions of the library.

The API

The NVM3 API is defined in the nvm3.h file, and the application code must include the nvm3.h header file to get access to all definitions, datatypes, and function prototypes defined by NVM3.

This section contains brief descriptions of NVM3 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.

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_getObjectInfo() , nvm3_enumObjects() , nvm3_deleteObject() and nvm3_countObjects()
These functions work on all objects. nvm3_enumObjects() gets a list of keys to valid objects in the NVM. The search can also be constrained by the function parameters. 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()
Write and read data objects.

nvm3_writeCounter() , nvm3_readCounter() and nvm3_incrementCounter()
Write, read, and increment 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 operations.

nvm3_resize()
Resize the NVM area used by an open NVM3 instance.

Memory Placement

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

  1. NVM area start address must be aligned with a page of the underlying memory system.
  2. NVM area size must be a multiple of the page size.

The minimum required NVM size is dependent on both the NVM page size and the NVM3_MAX_OBJECT_SIZE value. For a device with 2 kB page size and some typical values for NVM3_MAX_OBJECT_SIZE, the following is the minimum required number of pages:

  • For NVM3_MAX_OBJECT_SIZE=208: 3 pages
  • For NVM3_MAX_OBJECT_SIZE=1900: 4 pages
  • For NVM3_MAX_OBJECT_SIZE=4096: 5 pages

NVM3_DEFINE_SECTION_STATIC_DATA() and NVM3_DEFINE_SECTION_INIT_DATA() macros are provided to support the creation of the NVM area and initialization 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.

Note
When the start address and size of the data area has been defined and used by an application, it is important that the same values are used at every program startup and also re-used by new versions of the software after an upgrade. If an application tries to open an instance with a start address or size that does not mach previous use, it can result in permanent data loss and failure.

Configuration Options

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

Note
The Global Data (variables) must however be configured for correct size and have correct values for NVM3 to behave correctly.

Bad NVM Page Handling

NVM3 has been designed to detect page erase and write errors during normal operation and mark failing pages as BAD. If a write operation fails, all objects that have been written to the page prior to the write error are copied to the next free page before the page is marked as BAD and the write operation resumes. If the recover operation is successful, the operation is regarded as complete and the function will return ECODE_NVM3_OK status.

Note
Erase and write errors may not be detected by NVM3 if the device is used until end of life where the failure mode can be that the NVM content is changing during a power cycle.

Error Handling

The NVM3 error handling involves most functions returning an error code. The nvm3_countObjects is different because it returns the actual number of objects found.

The behavior and return values for most functions, such as nvm3_readData , nvm3_writeData , and so on should be self explanatory, while the nvm3_open is slightly different. nvm3_open will always try to recover from the previous state and continue without an error, if possible. In other words, if a valid NVM3 instance is established, nvm3_open will recover from brown outs and power cycles at any time in any operation and bring the system to a valid state where all pages and objects are in a known state and return success whenever possible. From this state, normal operation can resume. If nvm3_open returns an error, it's an indication of either a design or coding error, or that many of the NVM pages have been marked as BAD leaving insufficient space in the NVM to progress. Operation may not resume if nvm3_open returns an error.

Note
Because the nvm3_open may need to do recovery operations, the execution time will occasionally vary.

Storing objects in internal Flash

NVM3 has support for writing and reading objects in internal i.e., memory mapped Flash memory through the nvm3_hal_flash.c "driver". nvm3_hal_flash.c is using EMLIB functions to write and erase data, while using regular memory functions to read data from Flash.


The "driver" for internal Flash is selected by setting the halHandle in the nvm3_open initialization structure to point to nvm3_halFlashHandle.

NVM3 Libraries

The NVM3 comes with pre-compiled libraries for Cortex M0, M3, M4 and M33 compiled with either Arm GCC or IAR toolchains.

Storage Capacity

Basic storage is defined as the size of on instance of all objects including any overhead stored with the data. For NVM3 the maximum amount of data you can store is dependent on the number of flash pages used for storage and the max object size used for NVM3. The following table shows the maximum allowed basic storage for a varying number of 2 kB or 8 kB flash pages ,and the minimum (208 bytes), default (254 bytes), high (1900 bytes) and maximum (4096 bytes) max object size. Note that this is a theoretical limit and if the basic storage is at this limit, no space is left for wear-levelling and page erases will be forced for every object write. The NVM3 instance should therefore be configured with enough flash pages to put the maximum allowed basic storage significantly higher than the actual basic storage.

Max Allowed Basic Storage with 2 kB page size

Flash pages Total size (bytes) Max allowed basic storage (bytes)
Max object size = 208 bytes Max object size = 254 bytes Max object size = 1900 bytes Max object size = 4096 bytes
3 6144 1596 1504 0 0
4 8192 3624 3532 240 0
5 10240 5652 5560 2268 0
6 12288 7680 7588 4296 0
7 14336 9708 9616 6324 0
8 16384 11736 11644 8352 0
9 18432 13764 13672 10380 1900
10 20480 15792 15700 12408 3928
11 22528 17820 17728 14436 5956
12 24576 19848 19756 16464 7984
13 26624 21876 21784 18492 10012
14 28672 23904 23812 20520 12040
15 30720 25932 25840 22548 14068
16 32768 27960 27868 24576 16096
17 34816 29988 29896 26604 18124
18 36864 32016 31924 28632 20152

Max Allowed Basic Storage with 8 kB page size

Flash pages Total size (bytes) Max allowed basic storage (bytes)
Max object size = 208 bytes Max object size = 254 bytes Max object size = 1900 bytes Max object size = 4096 bytes
3 24516 7740 7648 4356 0
4 32688 15912 15820 12528 8136
5 40860 24084 23992 20700 16308
6 49032 32256 32164 28872 24480

Default Instance

Several NVM3 instances can be created on a device and live independently of each other, but to save memory it is usually desirable to use only one NVM3 instance as each instance adds some overhead. For this reason a default instance exists that is used by all Silicon Labs wireless stacks. The API to initialize the default instance and the handles to use with the regular NVM3 API is described in NVM3 Default Instance .

NVM3 in Simplicity Commander

Simplicity Commander is a single, all-purpose tool to be used in a production environment. It is invoked using a simple CLI (Command Line Interface) that is also scriptable. Simplicity Commander supports reading out the NVM3 data area from a device and parsing the NVM3 data to extract stored values. This can be useful in a debugging scenario where you may need to find out the stored state of an application that has been running for some time.

More information on how to use the Simplicity Commander with NVM3 can be found in UG162: Simplicity Commander Reference Guide.

Examples

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

#include "nvm3.h"
#include "nvm3_hal_flash.h"
// Create a NVM area of 24kB (size must equal N * FLASH_PAGE_SIZE, N is integer). Create a cache of 10 entries.
NVM3_DEFINE_SECTION_STATIC_DATA (nvm3Data1, 24576, 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_halFlashHandle );
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 };
uint32_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_getObjectInfo (&handle, 1, &objectType, &dataLen1);
if (objectType == NVM3_OBJECTTYPE_DATA ) {
nvm3_readData (&handle, 1, data1, dataLen1);
}
nvm3_getObjectInfo (&handle, 2, &objectType, &dataLen2);
if (objectType == NVM3_OBJECTTYPE_DATA ) {
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"
#include "nvm3_hal_flash.h"
// Create a NVM area of 24kB (size must equal N * FLASH_PAGE_SIZE, N is integer). Create a cache of 10 entries.
NVM3_DEFINE_SECTION_STATIC_DATA (nvm3Data2, 24576, 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_halFlashHandle );
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

NVM3 Default Instance
NVM3 default instance functions and handles.
NVM3 HAL
NVM3 Hardware Abstraction Layer.
NVM3 Lock
NVM3 lock functions.

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.

Functions

Ecode_t nvm3_open (nvm3_Handle_t *h, const nvm3_Init_t *i)
Open an NVM3 driver instance, which is represented by a handle keeping information about the state.
Ecode_t nvm3_close (nvm3_Handle_t *h)
Close the NVM3 driver instance.
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.
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_getObjectInfo (nvm3_Handle_t *h, nvm3_ObjectKey_t key, uint32_t *type, size_t *len)
Find the type and size of an object in NVM.
size_t nvm3_enumObjects (nvm3_Handle_t *h, nvm3_ObjectKey_t *keyListPtr, size_t keyListSize, nvm3_ObjectKey_t keyMin, nvm3_ObjectKey_t keyMax)
Create a list of object keys for valid objects in NVM.
size_t nvm3_enumDeletedObjects (nvm3_Handle_t *h, nvm3_ObjectKey_t *keyListPtr, size_t keyListSize, nvm3_ObjectKey_t keyMin, nvm3_ObjectKey_t keyMax)
Create a list of object keys for deleted objects in NVM.
Ecode_t nvm3_deleteObject (nvm3_Handle_t *h, nvm3_ObjectKey_t key)
Delete an object from NVM.
Ecode_t nvm3_writeCounter (nvm3_Handle_t *h, nvm3_ObjectKey_t key, uint32_t value)
Store a counter in NVM.
Ecode_t nvm3_readCounter (nvm3_Handle_t *h, nvm3_ObjectKey_t key, uint32_t *value)
Read a counter value from NVM.
Ecode_t nvm3_incrementCounter (nvm3_Handle_t *h, nvm3_ObjectKey_t key, uint32_t *newValue)
Increment a counter object value by 1 and read out optionally.
Ecode_t nvm3_eraseAll (nvm3_Handle_t *h)
Delete all objects 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.
void nvm3_setEraseCount (uint32_t eraseCnt)
Set the page erase count.
Ecode_t nvm3_repack (nvm3_Handle_t *h)
Execute a repack operation.
bool nvm3_repackNeeded (nvm3_Handle_t *h)
Check the internal status of NVM3 and return true if a repack operation is required.
Ecode_t nvm3_resize (nvm3_Handle_t *h, nvm3_HalPtr_t newAddr, size_t newSize)
Resize the NVM area used by an open NVM3 instance.
size_t nvm3_countObjects (nvm3_Handle_t *h)
Count valid objects.
size_t nvm3_countDeletedObjects (nvm3_Handle_t *h)
Count deleted objects.

Macros

#define ECODE_NVM3_OK ( ECODE_OK )
Success return value.
#define ECODE_NVM3_ERR_ALIGNMENT_INVALID ( ECODE_EMDRV_NVM3_BASE | 0x00000001U)
Invalid data alignment.
#define ECODE_NVM3_ERR_SIZE_TOO_SMALL ( ECODE_EMDRV_NVM3_BASE | 0x00000002U)
Not enough NVM memory specified.
#define ECODE_NVM3_ERR_NO_VALID_PAGES ( ECODE_EMDRV_NVM3_BASE | 0x00000003U)
Initialization aborted, no valid page found.
#define ECODE_NVM3_ERR_PAGE_SIZE_NOT_SUPPORTED ( ECODE_EMDRV_NVM3_BASE | 0x00000004U)
The page size is not supported.
#define ECODE_NVM3_ERR_OBJECT_SIZE_NOT_SUPPORTED ( ECODE_EMDRV_NVM3_BASE | 0x00000005U)
The object size is not supported.
#define ECODE_NVM3_ERR_STORAGE_FULL ( ECODE_EMDRV_NVM3_BASE | 0x00000006U)
No more NVM space available.
#define ECODE_NVM3_ERR_NOT_OPENED ( ECODE_EMDRV_NVM3_BASE | 0x00000007U)
The module has not been successfully opened.
#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_PARAMETER ( ECODE_EMDRV_NVM3_BASE | 0x00000009U)
Illegal parameter.
#define ECODE_NVM3_ERR_KEY_INVALID ( ECODE_EMDRV_NVM3_BASE | 0x0000000AU)
Invalid key value.
#define ECODE_NVM3_ERR_KEY_NOT_FOUND ( ECODE_EMDRV_NVM3_BASE | 0x0000000BU)
Key not found.
#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_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_ERASE_FAILED ( ECODE_EMDRV_NVM3_BASE | 0x0000000EU)
Erase failed.
#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 in the write operation.
#define ECODE_NVM3_ERR_READ_DATA_SIZE ( ECODE_EMDRV_NVM3_BASE | 0x00000011U)
Trying to read with a length different from actual object size.
#define ECODE_NVM3_ERR_READ_FAILED ( ECODE_EMDRV_NVM3_BASE | 0x00000012U)
Error in the read operation.
#define ECODE_NVM3_ERR_INIT_WITH_FULL_NVM ( ECODE_EMDRV_NVM3_BASE | 0x00000013U)
The module was opened with a full NVM.
#define ECODE_NVM3_ERR_RESIZE_PARAMETER ( ECODE_EMDRV_NVM3_BASE | 0x00000014U)
Illegal parameter.
#define ECODE_NVM3_ERR_RESIZE_NOT_ENOUGH_SPACE ( ECODE_EMDRV_NVM3_BASE | 0x00000015U)
Not enough NVM to complete resize.
#define ECODE_NVM3_ERR_ERASE_COUNT_ERROR ( ECODE_EMDRV_NVM3_BASE | 0x00000016U)
Erase counts are not valid.
#define ECODE_NVM3_ERR_ADDRESS_RANGE ( ECODE_EMDRV_NVM3_BASE | 0x00000017U)
Address and size is out of range of available NVM.
#define ECODE_NVM3_ERR_NVM_ACCESS ( ECODE_EMDRV_NVM3_BASE | 0x00000019U)
A NVM function call was failing.
#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_INT_ADDR_INVALID ( ECODE_EMDRV_NVM3_BASE | 0x00000021U)
Internal error trying to access invalid memory.
#define ECODE_NVM3_ERR_INT_KEY_MISMATCH ( ECODE_EMDRV_NVM3_BASE | 0x00000022U)
Key validation failure.
#define ECODE_NVM3_ERR_INT_SIZE_ERROR ( ECODE_EMDRV_NVM3_BASE | 0x00000023U)
Internal size mismatch error.
#define ECODE_NVM3_ERR_INT_EMULATOR ( ECODE_EMDRV_NVM3_BASE | 0x00000024U)
Internal Emulator error.
#define ECODE_NVM3_ERR_INT_TEST ( ECODE_EMDRV_NVM3_BASE | 0x00000030U)
Internal Test error.
#define NVM3_MIN_PAGE_SIZE 512U
Definitions of NVM3 constraints.
#define NVM3_MAX_OBJECT_SIZE_LOW_LIMIT 204U
The minimum value for the maximum object size.
#define NVM3_MAX_OBJECT_SIZE_HIGH_LIMIT 4096U
The maximum value for the maximum object size.
#define NVM3_MAX_OBJECT_SIZE_DEFAULT 1900U
The default value for the maximum object size.
#define NVM3_MAX_OBJECT_SIZE NVM3_MAX_OBJECT_SIZE_DEFAULT
The maximum object size.
#define NVM3_MIN_FRAGMENT_COUNT (2U)
The minimum number of fragments.
#define NVM3_DEFINE_SECTION_STATIC_DATA (name, nvmSize, cacheSize)
NVM3 static data definition helper macro for applications using linker script placement of the NVM memory area.
#define NVM3_DEFINE_SECTION_INIT_DATA (name, flashHandle)
NVM3 initialization data helper macro to be used with NVM3_DEFINE_SECTION_STATIC_DATA() .
#define NVM3_KEY_INVALID 0xFFFFFFFFU
Invalid key identifier.
#define NVM3_KEY_SIZE 20U
Unique object key identifier size in number of bits.
#define NVM3_KEY_MASK ((1U << NVM3_KEY_SIZE ) - 1U)
Unique object key identifier mask.
#define NVM3_KEY_MIN 0U
Minimum object key value.
#define NVM3_KEY_MAX NVM3_KEY_MASK
Maximum object key value.
#define NVM3_OBJECTTYPE_DATA 0U
The object is data.
#define NVM3_OBJECTTYPE_COUNTER 1U
The object is a counter.

Typedefs

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

Variables

nvm3_Obj_t nvm3_internalObjectHandleA
A variable used by the NVM3 functions.
nvm3_Obj_t nvm3_internalObjectHandleB
A variable used by the NVM3 functions.
nvm3_Obj_t nvm3_internalObjectHandleC
A variable used by the NVM3 functions.
nvm3_Obj_t nvm3_internalObjectHandleD
A variable used by the NVM3 functions.
const uint8_t nvm3_maxFragmentCount
A variable that must contain the maximum number of object fragments.
const size_t nvm3_objHandleSize
A variable containing the object handle size in bytes.

Function Documentation

◆ nvm3_open()

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

Open an NVM3 driver instance, which is represented by a handle keeping information about the state.

A successful open will initialize the handle and the cache with information about the objects already in the NVM-memory. Several NVM3 instances using different handles must NOT overlap NVM-memory. To change some of the parameters, first call nvm3_close and then nvm3_open .

Note
The driver handle must be initialized to zero before it is used the first time. The nvm3_open can be called repeatedly with the same handle and initialization data. In that case, the next calls will be regarded as a "no operation" and the function will return the same status as the previous call.
Parameters
[out] h A pointer to an NVM3 driver handle.
[in] i A pointer to NVM3 driver initialization data.
Returns
ECODE_NVM3_OK on success and a NVM3 Ecode_t on failure.

◆ nvm3_close()

Ecode_t nvm3_close ( nvm3_Handle_t * h )

Close the NVM3 driver instance.

Parameters
[in] h A pointer to the NVM3 driver handle.
Returns
ECODE_NVM3_OK is always returned.

◆ nvm3_writeData()

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.

If the data object exist with the same lenght, its old content is compared with the new and only if the new content is different from the old it will be written.

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.

◆ nvm3_readData()

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 data to this location.
[in] maxLen The maximum object size in number of bytes. The nvm3_getObjectInfo() function can be used to find the actual size.
Returns
ECODE_NVM3_OK on success or a NVM3 Ecode_t on failure.

◆ nvm3_getObjectInfo()

Ecode_t nvm3_getObjectInfo ( 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 writes the object size.
Returns
ECODE_NVM3_OK on success or a NVM3 Ecode_t on failure.

◆ nvm3_enumObjects()

size_t nvm3_enumObjects ( nvm3_Handle_t * h,
nvm3_ObjectKey_t * keyListPtr,
size_t keyListSize,
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] keyListPtr A pointer to a buffer for the key list.
[in] keyListSize The number of elements in the key list buffer. If the keyListSize = 0, the keyListPtr can be NULL and the function will return the total number of objects.
[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 keyListSize . If the keyListSize = 0, the function will return the total number of objects matching the key Min - Max pattern.

◆ nvm3_enumDeletedObjects()

size_t nvm3_enumDeletedObjects ( nvm3_Handle_t * h,
nvm3_ObjectKey_t * keyListPtr,
size_t keyListSize,
nvm3_ObjectKey_t keyMin,
nvm3_ObjectKey_t keyMax
)

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

Note
The function nvm3_countDeletedObjects() is also provided to count the number of deleted objects.
Parameters
[in] h A pointer to an NVM3 driver handle.
[out] keyListPtr A pointer to a buffer for the key list.
[in] keyListSize The number of elements in the key list buffer. If the keyListSize = 0, the keyListPtr can be NULL and the function will return the total number of objects.
[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 keyListSize . If the keyListSize = 0, the function will return the total number of objects matching the key Min - Max pattern.

◆ nvm3_deleteObject()

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.

◆ nvm3_writeCounter()

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.

◆ nvm3_readCounter()

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.

◆ nvm3_incrementCounter()

Ecode_t nvm3_incrementCounter ( nvm3_Handle_t * h,
nvm3_ObjectKey_t key,
uint32_t * newValue
)

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] newValue 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.

◆ nvm3_eraseAll()

Ecode_t nvm3_eraseAll ( nvm3_Handle_t * h )

Delete all objects in NVM.

Note
Users don't need to call this function to get NVM3 into an initial valid state.
Warning
The 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.

◆ nvm3_getEraseCount()

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 leveling 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.

◆ nvm3_setEraseCount()

void nvm3_setEraseCount ( uint32_t eraseCnt )

Set the page erase count.

Normally, the application should not be concerned with the erase count value. If NVM3 is substituting a previous solution, it is possible to transfer the erase count to NVM3 when initializing the NVM for the first time. The erase count must be set before the nvm3_open is called and will only take effect if the NVM is completely erased or contains unknown data to NVM3. In that case, all pages will be initialized with the supplied erase count. After nvm3_open is called, the value will be consumed and will have no effect on further calls to nvm3_open .

Parameters
[in] eraseCnt The erase count.

◆ nvm3_repack()

Ecode_t nvm3_repack ( nvm3_Handle_t * h )

Execute a repack operation.

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

Note
Calling nvm3_repack() is not mandatory 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 occurs by calling this function.

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

Parameters
[in] h A pointer to an NVM3 driver handle.
Returns
ECODE_NVM3_OK on success or a NVM3 Ecode_t on failure.

◆ nvm3_repackNeeded()

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 A pointer to an NVM3 driver handle.
Returns
true if repacking is needed, false if repacking is not needed.

◆ nvm3_resize()

Ecode_t nvm3_resize ( nvm3_Handle_t * h,
nvm3_HalPtr_t newAddr,
size_t newSize
)

Resize the NVM area used by an open NVM3 instance.

The area can be resized by changing the start or end address either up or down in memory. Because the input parameters to NVM3 are start address and size, users should be cautious. Either move the start address up or down in memory and adjust the size accordingly to keep the end address, or keep the address and change the size only. It is not possible to resize the area by doing changes in both ends of the NVM address range at the same time. If the resize operation returns ECODE_NVM3_OK , the instance is still open and can be used to access objects in the resized NVM. If the resize operation fails, the instance will still be open but with unchanged size.

Note
It is possible to decrease the NVM area to a new size that is not capable of keeping the already stored objects. The result is loss of data.
Parameters
[in] h A pointer to an NVM3 driver handle.
[in] newAddr The start address of the NVM after resize.
[in] newSize The size of the NVM after resize.
Returns
ECODE_NVM3_OK on success or a NVM3 Ecode_t on failure.

◆ nvm3_countObjects()

size_t nvm3_countObjects ( nvm3_Handle_t * h )
inline

Count valid objects.

Parameters
[in] h A pointer to an NVM3 driver handle.
Returns
The number of valid objects.

◆ nvm3_countDeletedObjects()

size_t nvm3_countDeletedObjects ( nvm3_Handle_t * h )
inline

Count deleted objects.

Parameters
[in] h A pointer to an NVM3 driver handle.
Returns
The number of deleted objects.

Macro Definition Documentation

◆ ECODE_NVM3_OK

#define ECODE_NVM3_OK   ( ECODE_OK )

Success return value.

◆ ECODE_NVM3_ERR_ALIGNMENT_INVALID

#define ECODE_NVM3_ERR_ALIGNMENT_INVALID   ( ECODE_EMDRV_NVM3_BASE | 0x00000001U)

Invalid data alignment.

◆ ECODE_NVM3_ERR_SIZE_TOO_SMALL

#define ECODE_NVM3_ERR_SIZE_TOO_SMALL   ( ECODE_EMDRV_NVM3_BASE | 0x00000002U)

Not enough NVM memory specified.

◆ ECODE_NVM3_ERR_NO_VALID_PAGES

#define ECODE_NVM3_ERR_NO_VALID_PAGES   ( ECODE_EMDRV_NVM3_BASE | 0x00000003U)

Initialization aborted, no valid page found.

◆ ECODE_NVM3_ERR_PAGE_SIZE_NOT_SUPPORTED

#define ECODE_NVM3_ERR_PAGE_SIZE_NOT_SUPPORTED   ( ECODE_EMDRV_NVM3_BASE | 0x00000004U)

The page size is not supported.

◆ ECODE_NVM3_ERR_OBJECT_SIZE_NOT_SUPPORTED

#define ECODE_NVM3_ERR_OBJECT_SIZE_NOT_SUPPORTED   ( ECODE_EMDRV_NVM3_BASE | 0x00000005U)

The object size is not supported.

◆ ECODE_NVM3_ERR_STORAGE_FULL

#define ECODE_NVM3_ERR_STORAGE_FULL   ( ECODE_EMDRV_NVM3_BASE | 0x00000006U)

No more NVM space available.

◆ ECODE_NVM3_ERR_NOT_OPENED

#define ECODE_NVM3_ERR_NOT_OPENED   ( ECODE_EMDRV_NVM3_BASE | 0x00000007U)

The module has not been successfully opened.

◆ ECODE_NVM3_ERR_OPENED_WITH_OTHER_PARAMETERS

#define ECODE_NVM3_ERR_OPENED_WITH_OTHER_PARAMETERS   ( ECODE_EMDRV_NVM3_BASE | 0x00000008U)

The module has already been opened with other parameters.

◆ ECODE_NVM3_ERR_PARAMETER

#define ECODE_NVM3_ERR_PARAMETER   ( ECODE_EMDRV_NVM3_BASE | 0x00000009U)

Illegal parameter.

◆ ECODE_NVM3_ERR_KEY_INVALID

#define ECODE_NVM3_ERR_KEY_INVALID   ( ECODE_EMDRV_NVM3_BASE | 0x0000000AU)

Invalid key value.

◆ ECODE_NVM3_ERR_KEY_NOT_FOUND

#define ECODE_NVM3_ERR_KEY_NOT_FOUND   ( ECODE_EMDRV_NVM3_BASE | 0x0000000BU)

Key not found.

◆ ECODE_NVM3_ERR_OBJECT_IS_NOT_DATA

#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.

◆ ECODE_NVM3_ERR_OBJECT_IS_NOT_A_COUNTER

#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.

◆ ECODE_NVM3_ERR_ERASE_FAILED

#define ECODE_NVM3_ERR_ERASE_FAILED   ( ECODE_EMDRV_NVM3_BASE | 0x0000000EU)

Erase failed.

◆ ECODE_NVM3_ERR_WRITE_DATA_SIZE

#define ECODE_NVM3_ERR_WRITE_DATA_SIZE   ( ECODE_EMDRV_NVM3_BASE | 0x0000000FU)

The object is too large.

◆ ECODE_NVM3_ERR_WRITE_FAILED

#define ECODE_NVM3_ERR_WRITE_FAILED   ( ECODE_EMDRV_NVM3_BASE | 0x00000010U)

Error in the write operation.

◆ ECODE_NVM3_ERR_READ_DATA_SIZE

#define ECODE_NVM3_ERR_READ_DATA_SIZE   ( ECODE_EMDRV_NVM3_BASE | 0x00000011U)

Trying to read with a length different from actual object size.

◆ ECODE_NVM3_ERR_READ_FAILED

#define ECODE_NVM3_ERR_READ_FAILED   ( ECODE_EMDRV_NVM3_BASE | 0x00000012U)

Error in the read operation.

◆ ECODE_NVM3_ERR_INIT_WITH_FULL_NVM

#define ECODE_NVM3_ERR_INIT_WITH_FULL_NVM   ( ECODE_EMDRV_NVM3_BASE | 0x00000013U)

The module was opened with a full NVM.

◆ ECODE_NVM3_ERR_RESIZE_PARAMETER

#define ECODE_NVM3_ERR_RESIZE_PARAMETER   ( ECODE_EMDRV_NVM3_BASE | 0x00000014U)

Illegal parameter.

◆ ECODE_NVM3_ERR_RESIZE_NOT_ENOUGH_SPACE

#define ECODE_NVM3_ERR_RESIZE_NOT_ENOUGH_SPACE   ( ECODE_EMDRV_NVM3_BASE | 0x00000015U)

Not enough NVM to complete resize.

◆ ECODE_NVM3_ERR_ERASE_COUNT_ERROR

#define ECODE_NVM3_ERR_ERASE_COUNT_ERROR   ( ECODE_EMDRV_NVM3_BASE | 0x00000016U)

Erase counts are not valid.

◆ ECODE_NVM3_ERR_ADDRESS_RANGE

#define ECODE_NVM3_ERR_ADDRESS_RANGE   ( ECODE_EMDRV_NVM3_BASE | 0x00000017U)

Address and size is out of range of available NVM.

◆ ECODE_NVM3_ERR_NVM_ACCESS

#define ECODE_NVM3_ERR_NVM_ACCESS   ( ECODE_EMDRV_NVM3_BASE | 0x00000019U)

A NVM function call was failing.

◆ ECODE_NVM3_ERR_INT_WRITE_TO_NOT_ERASED

#define ECODE_NVM3_ERR_INT_WRITE_TO_NOT_ERASED   ( ECODE_EMDRV_NVM3_BASE | 0x00000020U)

Write to memory that is not erased.

◆ ECODE_NVM3_ERR_INT_ADDR_INVALID

#define ECODE_NVM3_ERR_INT_ADDR_INVALID   ( ECODE_EMDRV_NVM3_BASE | 0x00000021U)

Internal error trying to access invalid memory.

◆ ECODE_NVM3_ERR_INT_KEY_MISMATCH

#define ECODE_NVM3_ERR_INT_KEY_MISMATCH   ( ECODE_EMDRV_NVM3_BASE | 0x00000022U)

Key validation failure.

◆ ECODE_NVM3_ERR_INT_SIZE_ERROR

#define ECODE_NVM3_ERR_INT_SIZE_ERROR   ( ECODE_EMDRV_NVM3_BASE | 0x00000023U)

Internal size mismatch error.

◆ ECODE_NVM3_ERR_INT_EMULATOR

#define ECODE_NVM3_ERR_INT_EMULATOR   ( ECODE_EMDRV_NVM3_BASE | 0x00000024U)

Internal Emulator error.

◆ ECODE_NVM3_ERR_INT_TEST

#define ECODE_NVM3_ERR_INT_TEST   ( ECODE_EMDRV_NVM3_BASE | 0x00000030U)

Internal Test error.

◆ NVM3_MIN_PAGE_SIZE

#define NVM3_MIN_PAGE_SIZE   512U

Definitions of NVM3 constraints.

The minimum page size supported

◆ NVM3_MAX_OBJECT_SIZE_LOW_LIMIT

#define NVM3_MAX_OBJECT_SIZE_LOW_LIMIT   204U

The minimum value for the maximum object size.

◆ NVM3_MAX_OBJECT_SIZE_HIGH_LIMIT

#define NVM3_MAX_OBJECT_SIZE_HIGH_LIMIT   4096U

The maximum value for the maximum object size.

◆ NVM3_MAX_OBJECT_SIZE_DEFAULT

#define NVM3_MAX_OBJECT_SIZE_DEFAULT   1900U

The default value for the maximum object size.

◆ NVM3_MAX_OBJECT_SIZE

#define NVM3_MAX_OBJECT_SIZE NVM3_MAX_OBJECT_SIZE_DEFAULT

The maximum object size.

◆ NVM3_MIN_FRAGMENT_COUNT

#define NVM3_MIN_FRAGMENT_COUNT   (2U)

The minimum number of fragments.

◆ NVM3_DEFINE_SECTION_STATIC_DATA

#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 the NVM memory area.

This macro exports the section 'name'_section to the linker. The user must place the section name 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 the 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.

◆ NVM3_DEFINE_SECTION_INIT_DATA

#define NVM3_DEFINE_SECTION_INIT_DATA ( name,
flashHandle
)
Value:
nvm3_Init_t name = \
{ \
( nvm3_HalPtr_t )name##_nvm, \
sizeof (name##_nvm), \
name##_cache, \
sizeof(name##_cache) / sizeof (nvm3_CacheEntry_t), \
NVM3_MAX_OBJECT_SIZE , \
0, \
flashHandle, \
}

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.

◆ NVM3_KEY_INVALID

#define NVM3_KEY_INVALID   0xFFFFFFFFU

Invalid key identifier.

◆ NVM3_KEY_SIZE

#define NVM3_KEY_SIZE   20U

Unique object key identifier size in number of bits.

◆ NVM3_KEY_MASK

#define NVM3_KEY_MASK   ((1U << NVM3_KEY_SIZE ) - 1U)

Unique object key identifier mask.

◆ NVM3_KEY_MIN

#define NVM3_KEY_MIN   0U

Minimum object key value.

◆ NVM3_KEY_MAX

#define NVM3_KEY_MAX NVM3_KEY_MASK

Maximum object key value.

◆ NVM3_OBJECTTYPE_DATA

#define NVM3_OBJECTTYPE_DATA   0U

The object is data.

◆ NVM3_OBJECTTYPE_COUNTER

#define NVM3_OBJECTTYPE_COUNTER   1U

The object is a counter.

Typedef Documentation

◆ nvm3_ObjectKey_t

typedef uint32_t nvm3_ObjectKey_t

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

Variable Documentation

◆ nvm3_internalObjectHandleA

nvm3_Obj_t nvm3_internalObjectHandleA

A variable used by the NVM3 functions.

◆ nvm3_internalObjectHandleB

nvm3_Obj_t nvm3_internalObjectHandleB

A variable used by the NVM3 functions.

◆ nvm3_internalObjectHandleC

nvm3_Obj_t nvm3_internalObjectHandleC

A variable used by the NVM3 functions.

◆ nvm3_internalObjectHandleD

nvm3_Obj_t nvm3_internalObjectHandleD

A variable used by the NVM3 functions.

◆ nvm3_maxFragmentCount

const uint8_t nvm3_maxFragmentCount

A variable that must contain the maximum number of object fragments.

◆ nvm3_objHandleSize

const size_t nvm3_objHandleSize

A variable containing the object handle size in bytes.