Non-Volatile Storage

The NVS module provides a key-value store backed by non-volatile memory (flash, EEPROM, or host filesystem depending on the backend).

Architecture

graph LR
    APP["Application"] --> API["ove_nvs API"]
    API --> BE["Backend"]
    BE --> FreeRTOS["FreeRTOS<br/><small>LittleFS / flash</small>"]
    BE --> Zephyr["Zephyr<br/><small>NVS subsystem</small>"]
    BE --> NuttX["NuttX<br/><small>/dev/config</small>"]
    BE --> POSIX["POSIX<br/><small>~/.ove-nvs/ files</small>"]

    style API fill:#48b,stroke:#333,color:#fff

API Reference

Function	Description
ove_nvs_init()	Initialize the NVS subsystem (call once at startup)
ove_nvs_deinit()	Tear down the NVS subsystem
ove_nvs_read(key, buf, buf_len, &out_len)	Read value by key. Pass buf=NULL to query size only.
ove_nvs_write(key, data, len)	Write or update a key-value pair
ove_nvs_erase(key)	Delete a key-value pair

Usage

/* Initialize */
ove_nvs_init();

/* Write a setting */
uint8_t bypass = 1;
ove_nvs_write("bypass", &bypass, sizeof(bypass));

/* Read it back */
uint8_t val = 0;
size_t out_len = 0;
if (ove_nvs_read("bypass", &val, sizeof(val), &out_len) == OVE_OK) {
    /* val == 1, out_len == 1 */
}

/* Delete */
ove_nvs_erase("bypass");

Error Codes

Code	Meaning
OVE_OK	Success
OVE_ERR_INVALID_PARAM	NULL key or invalid arguments
OVE_ERR_NOT_SUPPORTED	CONFIG_OVE_NVS not enabled

Kconfig

Option	Default	Description
CONFIG_OVE_NVS	y	Enable non-volatile key-value storage

Header

ove/nvs.h