wifi scan in non-blocking mode

[ry1234]

Hi

I would like to use esp_wifi_scan_start() in non-blocking mode; is there an API or register that allows to check if the scan has completed?

Thanks!

[WiFive]

SYSTEM_EVENT_SCAN_DONE

https://github.com/espressif/esp-idf/bl ... vent.h#L31

[ry1234]

Thanks for that.

Does the wifi_scan_start() api initiate an active scan or a passive scan (or both)? I would like to limit to active scan only, couldn't find a way so far to control the behavior beyond a brief mention in the data sheet.

Thanks!

[kolban]

Howdy ry1234,
Purely because I are a dummy ... can you explain the distinction between an "Active" WiFi scan and a "Passive" WiFi scan?

Neil

[ry1234]

Hi Neil,
Passive scanning is where the client listens to the beacon broadcasts (typical beacon interval is 100 msec).
Active scanning is where the client transmits a probe request and waits for a probe response from all SSIDs that received the request.

[ry1234]

Hi,

Another piece of information: the esp_wifi_scan_start() API takes 200 msec to return, for a single Wifi channel:

wifi_scan_config_t cfg = {NULL, NULL, 1, false};
ESP_ERROR_CHECK( esp_wifi_scan_start(&cfg, true));

So I suspect it is performing a passive scan (?)