AutoConnect/mkdocs/credit.md

Saved credentials in EEPROM

AutoConnect stores the established WiFi connection in the EEPROM of the ESP8266/ESP32 module and equips the class to access it from the sketch. You can read, write or erase the credentials using this class individually. It's AutoConnectCredential class which provides the access method to the saved credentials in EEPROM.¹

AutoConnectCredential

Include header

#include <AutoConnectCredential.h>

Constructors

AutoConnectCredential();

AutoConnectCredential default constructor. The default offset value is 0. If the offset value is 0, the credential area starts from the top of the EEPROM. AutoConnect sometimes overwrites data when using this area with user sketch.

AutoConnectCredential(uint16_t offset);

**Parameter**

offsetSpecies offset from the top of the EEPROM for the credential area together. The offset value is from 0 to the flash sector size.

Public member functions

entries

uint8_t entries(void)

Returns number of entries as contained credentials.

**Return value**

Number of entries as contained credentials.

load

int8_t load(const char* ssid, struct station_config* config)

Load a credential entry and store to config.

**Parameters**

ssidSSID to be loaded.

configstation_config

**Return value**

Save the specified SSID's credential entry to station_config pointed to by the parameter as **config**. -1 is returned if the SSID is not saved.

load

bool load(int8_t entry, struct station_config* config)

Load a credential entry and store to config.

**Parameters**

entrySpecifies the index number based 0 to be loaded.

configstation_config

**Return value**

Save the specified credential entry to station_config pointed to by the parameter as **config**. -1 is returned if specified number is not saved.

save

bool save(const struct station_config* config)

Save a credential entry.

**Parameter**

configstation_config to be saved.

**Return value**

trueSuccessfully saved.

falseFailed to save.

del

bool del(const char* ssid)

Delete a credential the specified SSID.

**Parameter**

ssidSSID to be deleted.

**Return value**

trueSuccessfully deleted.

falseFailed to delete.

The data structures

station_config

A structure is included in the ESP8266 SDK. You can use it in the sketch like as follows:

extern "C" {
#include <user_interface.h>
}

struct station_config {
  uint8 ssid[32];
  uint8 password[64];
  uint8 bssid_set;
  uint8 bssid[6];
};

The credential entry

A data structure of the credential saving area in EEPROM as the below. ²

There may be 0xff as an invalid data in the credential saving area. The 0xff area would be reused.

Byte offset	Length	Value
0	8	AC_CREDT
8	1	Number of contained entries (uint8_t)
9	2	Container size, excluding size of AC_CREDT and size of the number of entries(width for uint16_t type).
11	variable	SSID terminated by 0x00. Max length is 32 bytes.
variable	variable	Password plain text terminated by 0x00. Max length is 64 bytes.
variable	6	BSSID
variable		Contained the next entries. (Continuation SSID+Password+BSSID)
variable	1	0x00. End of container.

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1. An example using AutoConnectCredential is provided as an example of a library sketch to delete saved credentials. ↩︎

2. ↩︎