Q: Which API need to call in user_init

[ESP_Greg]

Q: Which API need to call in user_init

wifi_set_ip_info and wifi_set_macaddr can only be called in user_init, it will be valid if called at anywhere else.

system_timer_reinit is suggested to call in user_init. If it's called anywhere else, need to arm all timer again.

wifi_station_set_config, if it's called in user_init, phy layer will connect router automatically, no need to call wifi_station_connect again. Or need to call wifi_station_connect if you want to set a connection.

wifi_station_set_auto_connect will set if need to connect to router automatically. For example, if you want to close automatically connection, a) you call wifi_station_set_auto_connect in user_init, then automatically connection will close this time; b) you call wifi_station_set_auto_connect somewhere else, automatically connection will close after next boot.