esp_bus Events

ESP WiFi Config uses esp_bus for event-driven communication. Your application subscribes to events rather than polling for state changes.

Prerequisites

#include "esp_bus.h"

// esp_bus must be initialized before wifi_cfg_init
esp_bus_init();

Available Events

Subscribe using the WIFI_EVT() macro, which generates the full event name string:

esp_bus_sub(WIFI_EVT(WIFI_CFG_EVT_CONNECTED), on_connected, NULL);

Event	Payload Type	Description
WIFI_CFG_EVT_CONNECTED	wifi_connected_t	STA connected to an AP
WIFI_CFG_EVT_DISCONNECTED	wifi_disconnected_t	STA disconnected from AP
WIFI_CFG_EVT_GOT_IP	wifi_got_ip_t	STA obtained an IP address
WIFI_CFG_EVT_SCAN_DONE	wifi_scan_done_t	WiFi scan completed
WIFI_CFG_EVT_NETWORK_ADDED	wifi_network_changed_t	A network was added or updated
WIFI_CFG_EVT_VAR_CHANGED	wifi_var_changed_t	A custom variable was changed
WIFI_CFG_EVT_PROVISIONING_STARTED	NULL	Provisioning interfaces started
WIFI_CFG_EVT_PROVISIONING_STOPPED	NULL	Provisioning interfaces stopped

Callback Signature

All event callbacks use the same signature:

void callback(const char *event, const void *data, size_t len, void *ctx)

• event — The event name string
• data — Pointer to the payload struct (cast to the appropriate type)
• len — Size of the payload
• ctx — User context pointer (passed when subscribing)

Example: Subscribing to Events

static void on_connected(const char *event, const void *data, size_t len, void *ctx)
{
    wifi_connected_t *info = (wifi_connected_t *)data;
    ESP_LOGI(TAG, "Connected to %s, RSSI: %d", info->ssid, info->rssi);
}

static void on_disconnected(const char *event, const void *data, size_t len, void *ctx)
{
    wifi_disconnected_t *info = (wifi_disconnected_t *)data;
    ESP_LOGI(TAG, "Disconnected from %s, reason: %d", info->ssid, info->reason);
}

static void on_got_ip(const char *event, const void *data, size_t len, void *ctx)
{
    wifi_got_ip_t *info = (wifi_got_ip_t *)data;
    ESP_LOGI(TAG, "Got IP: %s", info->ip);
}

static void on_scan_done(const char *event, const void *data, size_t len, void *ctx)
{
    ESP_LOGI(TAG, "WiFi scan completed");
}

// Subscribe to all events
esp_bus_sub(WIFI_EVT(WIFI_CFG_EVT_CONNECTED), on_connected, NULL);
esp_bus_sub(WIFI_EVT(WIFI_CFG_EVT_DISCONNECTED), on_disconnected, NULL);
esp_bus_sub(WIFI_EVT(WIFI_CFG_EVT_GOT_IP), on_got_ip, NULL);
esp_bus_sub(WIFI_EVT(WIFI_CFG_EVT_SCAN_DONE), on_scan_done, NULL);
esp_bus_sub(WIFI_EVT(WIFI_CFG_EVT_NETWORK_ADDED), on_network_added, NULL);
esp_bus_sub(WIFI_EVT(WIFI_CFG_EVT_VAR_CHANGED), on_var_changed, NULL);
esp_bus_sub(WIFI_EVT(WIFI_CFG_EVT_PROVISIONING_STARTED), on_prov_started, NULL);
esp_bus_sub(WIFI_EVT(WIFI_CFG_EVT_PROVISIONING_STOPPED), on_prov_stopped, NULL);

Event Timing

• CONNECTED fires when the WiFi STA association completes (before IP assignment)
• GOT_IP fires when DHCP assigns an IP address — this is typically the event you want to trigger application logic
• PROVISIONING_STOPPED fires after the teardown delay (provisioning_teardown_delay_ms) when stop_provisioning_on_connect is true