ESP starts in AP_STA after Wifi.begin although WiFi.Mode(WIFI_STA) using staging package

I've switched to the staging package, because it supports NodeMCU V1.0 and has some important fixes included. But the project that I'm running now suddenly starts in AP_STA mode instead of STA only. Code used is 100% unchanged.

I've have created a simple test sketch to demonstrate the issue:

include <ESP8266WiFi.h>

void setup()
{
Serial.begin(115200);
Serial.setDebugOutput(true);

Serial.println("Config AP");
WiFi.softAP("ESP_DEMO", "secure");

Serial.println("Set to STA mode");
WiFi.mode(WIFI_STA);

Serial.println("Wifi begin");
WiFi.begin("MYAP", "********");
}

output using package 1.6.4-673-g8cd3697 (may 22nd)

Config AP
mode : sta(18:fe:34:a6:d6:84) + softAP(1a:fe:34:a6:d6:84)
dhcp server start:(ip:192.168.4.1,mask:255.255.255.0,gw:192.168.4.1
add if1
bcn 100
Set to STA mode
bcn 0
del if1
mode : sta(18:fe:34:a6:d6:84)
Wifi begin

output using package 1.6.5-804-g2d340c7 (june 26th)

Config AP
scandone
del if0
mode : softAP(1a:fe:34:a6:d6:84)
Set to STA mode
bcn 0
del if1
usl
sul 0 0
mode : sta(18:fe:34:a6:d6:84)
add if0
Wifi begin
mode : sta(18:fe:34:a6:d6:84) + softAP(1a:fe:34:a6:d6:84)

as you can see (last line) it now starts sta + softAP ! after Wifi.begin command....

[noahwilliamsson]

The code in hardware/esp8266com/esp8266/libraries/ESP8266WiFi/src/ESP8266WiFi.cpp is definitely buggy in its current state.

Once you call WiFi.softAP(), the code internally sets the flag _useApMode = true. This flag is then used in multiple places to decide what the actual desired mode should be when turning on station mode (e.g. WiFi.begin()) or turning it off (e.g. WiFi.disconnect()).

For instance, if you have called WiFi.softAP() once, the flag will be true, and WiFi.begin() will consider it and set the mode to WIFI_AP_STA (as opposed to WIFI_AP if the flag wasn't set, which happens to be the default).

Unfortunately there is no corresponding _useApMode = false. Furthermore, the flags _useApMode and _useClientMode are not updated to reflect the reality after changing modes with WiFi.mode().

Until this is fixed, I suppose you could either avoid calling WiFi.softAP() if you're not going to actually use it, or call WiFi.mode(WIFI_STA) after WiFi.begin() if you've called WiFi.softAP().

[martinayotte]

Actually, with the current version, _useApMode is always false from the constructor.
But effectively, those flags are not reflecting the real mode.
Also, I found a strange thing related to that : If we have an AP serving a web page to show existing network for future STA connection, the scanNetworks() will stop the AP mode and the current client will be disconnected.

[Links2004]

please retry in last release,
If it still a problem feel free to reopen.

[gosewski]

I think, in this case the main problem with switching WiFi mode in taht the used password "secure" do not fullfils the minimal length requirement which is 8 characters. In such case WiFi.softAP function returns false and the mode remains unchanged.

[sarwadenj]

on reboot esp8266 starts in which mode.
AP or station mode