A few questions and things I've noticed about Wifi.
Posted: Thu Sep 13, 2018 10:40 am
Hello again,
So as you may have guessed from the title of this topic, I have a few questions and some other oddities I've noticed about the wifi system.
First, I'm wondering about the return codes of esp_wifi_connect.
The doxygen for esp_wifi_connect mentions a return code ESP_ERR_WIFI_SSID, describing the SSID you are connecting to being invalid:
So I just tested this with a bogus SSID which doesn't exist at all, using the console system to switch the SSID's around:
So as you can see, the wifi system properly disconnects and then attempts to connect to this SSID. But there's no mention of an improper SSID, see the code:
So there's no logging message about an invalid SSID, as I would have expected. Perhaps this is an oversight of some kind?
EDIT:
Putting the log output in debug gives me the following:
The second thing is that sometimes the ESP32 simply refuses to connect to an AP until you restart the entire system, even when you have de-inited Wifi and re-inited, and you're trying to connect to an AP you have already been connected to in the past, so you know the SSID and password are correct.
We are running this software on a device that is meant to be online as much as possible, and sometimes the connection simply fails. When this happens, a monitoring task attempts to reconnect the Wifi to the given SSID say, 6 times. If after these 6 attempts there is still no connection with the SSID, the task will de-init and reinit the Wifi system entirely and attempt again. Most of the time this will not work, and then the task software-restarts the ESP32. And then it does work. I would expect de-initializing the wifi system through esp_wifi_deinit to work with these function calls:
So as you may have guessed from the title of this topic, I have a few questions and some other oddities I've noticed about the wifi system.
First, I'm wondering about the return codes of esp_wifi_connect.
The doxygen for esp_wifi_connect mentions a return code ESP_ERR_WIFI_SSID, describing the SSID you are connecting to being invalid:
Code: Select all
/**
* @brief Connect the ESP32 WiFi station to the AP.
*
* @attention 1. This API only impact WIFI_MODE_STA or WIFI_MODE_APSTA mode
* @attention 2. If the ESP32 is connected to an AP, call esp_wifi_disconnect to disconnect.
*
* @return
* - ESP_OK: succeed
* - ESP_ERR_WIFI_NOT_INIT: WiFi is not initialized by esp_wifi_init
* - ESP_ERR_WIFI_NOT_START: WiFi is not started by esp_wifi_start
* - ESP_ERR_WIFI_CONN: WiFi internal error, station or soft-AP control block wrong
* - ESP_ERR_WIFI_SSID: SSID of AP which station connects is invalid
*/
esp_err_t esp_wifi_connect(void);Code: Select all
comms wifi ssid=bla pw=bla
I (68600) WIFI: Attempting to connect to network bla...
I (68602) WIFI: Disconnecting from current network... // Already connected to some other network, I'll show the code later.
I (68619) wifi: state: run -> init (0)
I (68621) wifi: pm stop, total sleep time: 62646848 us / 66897955 us
I (68622) wifi: n:6 0, o:6 0, ap:255 255, sta:6 0, prof:1
I (68634) COMMS: Sta Disconnected // This is printed by the event handler I've defined.
I (68736) MQTT: We lost connection!
I (68737) MQTTmbedtls: NetworkDisconnect
W (68741) MQTT: Reconnecting MQTT, attempt 1 of 2...
I (68741) MQTT: MQTTClientInit (attempt 1 of 2)...
I (68752) MQTT: Sleeping until there is a network connection (Max 30s)
I (69635) WIFI: Waiting for ip address (15 sec)...
I (72044) COMMS: Sta Disconnected
E (84636) WIFI: Timeout.Code: Select all
esp_err_t my_wifi_connect(const char* ssid, int ssid_len, const char* pw, int pw_len)
{
ESP_LOGI(TAG, "Attempting to connect to network %s...", ssid);
wifi_config_t conf = { 0 };
conf.sta.bssid_set = false;
wifi_ap_record_t curr_station;
esp_err_t err = esp_wifi_sta_get_ap_info(&curr_station);
// check if ESP currently has connection already
if (err == ESP_OK)
{
// already connected with requested SSID
if (strcmp((const char*)curr_station.ssid, ssid) == 0)
{
ESP_LOGI(TAG, "Already connected to network %s", ssid);
return ESP_OK;
}
else
{
// not connected with requested SSID
if (strlen((char*)curr_station.ssid) > 0)
{
ESP_LOGI(TAG, "Disconnecting from current network...");
esp_wifi_disconnect();
WAIT(1000); // give the event task time to send the appropriate events - vTaskDelay macro wrapper
}
}
}
wificonf_copy_credentials(&conf, false, ssid, ssid_len, pw, pw_len);
CHECK_ERR(TAG, esp_wifi_set_config(WIFI_IF_STA, &conf));
err = esp_wifi_connect();
if (err != ESP_OK)
{
ESP_LOGE(TAG, "%s wifi connect err %d", __func__, err); // Where is ESP_ERR_WIFI_SSID?
}
return err;
}EDIT:
Putting the log output in debug gives me the following:
Code: Select all
D (31008) event: SYSTEM_EVENT_STA_DISCONNECTED, ssid:bla, ssid_len:3, bssid:00:00:00:00:00:00, reason:201
D (31009) tcpip_adapter: if0 start ip lost tmr: enter
D (31020) tcpip_adapter: if0 start ip lost tmr: already startedWe are running this software on a device that is meant to be online as much as possible, and sometimes the connection simply fails. When this happens, a monitoring task attempts to reconnect the Wifi to the given SSID say, 6 times. If after these 6 attempts there is still no connection with the SSID, the task will de-init and reinit the Wifi system entirely and attempt again. Most of the time this will not work, and then the task software-restarts the ESP32. And then it does work. I would expect de-initializing the wifi system through esp_wifi_deinit to work with these function calls:
Code: Select all
esp_wifi_disconnect();
esp_wifi_stop();
esp_wifi_deinit();
vTaskDelay(2500 / portTICK_PERIOD_MS); // to give the event task time to send the appropriate events
// esp_wifi_init, set_storage, set_mode, start, etc.