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class WLAN – control built-in WiFi interfaces

This class provides a driver for WiFi network processors. Example usage:

import network
# enable station interface and connect to WiFi access point
nic = network.WLAN(network.WLAN.IF_STA)
nic.active(True)
nic.connect('your-ssid', 'your-key')
# now use sockets as usual

Constructors

class network.WLAN(interface_id)

Create a WLAN network interface object. Supported interfaces are network.WLAN.IF_STA (station aka client, connects to upstream WiFi access points) and network.WLAN.IF_AP (access point, allows other WiFi clients to connect). Availability of the methods below depends on interface type. For example, only STA interface may WLAN.connect() to an access point.

Methods

WLAN.active([is_active])

Activate (“up”) or deactivate (“down”) network interface, if boolean argument is passed. Otherwise, query current state if no argument is provided. Most other methods require active interface.

WLAN.connect(ssid=None, key=None, *, bssid=None)

Connect to the specified wireless network, using the specified key. If bssid is given then the connection will be restricted to the access-point with that MAC address (the ssid must also be specified in this case).

WLAN.disconnect()

Disconnect from the currently connected wireless network.

WLAN.scan()

Scan for the available wireless networks. Hidden networks – where the SSID is not broadcast – will also be scanned if the WLAN interface allows it.

Scanning is only possible on STA interface. Returns list of tuples with the information about WiFi access points:

(ssid, bssid, channel, RSSI, security, hidden)

bssid is hardware address of an access point, in binary form, returned as bytes object. You can use binascii.hexlify() to convert it to ASCII form.

There are five values for security:

  • 0 – open

  • 1 – WEP

  • 2 – WPA-PSK

  • 3 – WPA2-PSK

  • 4 – WPA/WPA2-PSK

and two for hidden:

  • 0 – visible

  • 1 – hidden

WLAN.status([param])

Return the current status of the wireless connection.

When called with no argument the return value describes the network link status. The possible statuses are defined as constants in the network module:

  • STAT_IDLE – no connection and no activity,

  • STAT_CONNECTING – connecting in progress,

  • STAT_WRONG_PASSWORD – failed due to incorrect password,

  • STAT_NO_AP_FOUND – failed because no access point replied,

  • STAT_CONNECT_FAIL – failed due to other problems,

  • STAT_GOT_IP – connection successful.

When called with one argument param should be a string naming the status parameter to retrieve, and different parameters are supported depending on the mode the WiFi is in.

In STA mode, passing 'rssi' returns a signal strength indicator value, whose format varies depending on the port (this is available on all ports that support WiFi network interfaces, except for CC3200).

In AP mode, passing 'stations' returns a list of connected WiFi stations (this is available on all ports that support WiFi network interfaces, except for CC3200). The format of the station information entries varies across ports, providing either the raw BSSID of the connected station, the IP address of the connected station, or both.

WLAN.isconnected()

In case of STA mode, returns True if connected to a WiFi access point and has a valid IP address. In AP mode returns True when a station is connected. Returns False otherwise.

WLAN.ifconfig([(ip, subnet, gateway, dns)])

Get/set IP-level network interface parameters: IP address, subnet mask, gateway and DNS server. When called with no arguments, this method returns a 4-tuple with the above information. To set the above values, pass a 4-tuple with the required information. For example:

nic.ifconfig(('192.168.0.4', '255.255.255.0', '192.168.0.1', '8.8.8.8'))
WLAN.config('param')
WLAN.config(param=value, ...)

Get or set general network interface parameters. These methods allow to work with additional parameters beyond standard IP configuration (as dealt with by AbstractNIC.ipconfig()). These include network-specific and hardware-specific parameters. For setting parameters, keyword argument syntax should be used, multiple parameters can be set at once. For querying, parameters name should be quoted as a string, and only one parameter can be queries at time:

# Set WiFi access point name (formally known as SSID) and WiFi channel
ap.config(ssid='My AP', channel=11)
# Query params one by one
print(ap.config('ssid'))
print(ap.config('channel'))

Following are commonly supported parameters (availability of a specific parameter depends on network technology type, driver, and MicroPython port).

Parameter

Description

mac

MAC address (bytes)

ssid

WiFi access point name (string)

channel

WiFi channel (integer). Depending on the port this may only be supported on the AP interface.

hidden

Whether SSID is hidden (boolean)

security

Security protocol supported (enumeration, see module constants)

key

Access key (string)

hostname

The hostname that will be sent to DHCP (STA interfaces) and mDNS (if supported, both STA and AP). (Deprecated, use network.hostname() instead)

reconnects

Number of reconnect attempts to make (integer, 0=none, -1=unlimited)

txpower

Maximum transmit power in dBm (integer or float)

pm

WiFi Power Management setting (see below for allowed values)

protocol

(ESP32 Only.) WiFi Low level 802.11 protocol. See WLAN.PROTOCOL_DEFAULT.

bandwidth

(ESP32 Only.) WiFi channel bandwidth. See WLAN.BANDWIDTH_20 and others.

CSI Methods (ESP32 only)

Note

These methods are only available on ESP32 builds with CSI support enabled. The standard generic ESP32, ESP32-C3, ESP32-C5, ESP32-C6, and ESP32-S3 board definitions enable this in their default configuration. Other builds need CONFIG_ESP_WIFI_CSI_ENABLED=y in the ESP-IDF configuration.

Channel State Information (CSI) provides per-packet physical layer channel data derived from received Wi-Fi frames. CSI capture requires an active Wi-Fi connection and incoming traffic to the device. Without traffic, no CSI frames will be captured.

Other Espressif CSI options are hard-coded to defaults intended for connected station capture.

WLAN.csi_enable(buffer_size=16)

Enable CSI capture and allocate a circular buffer for received frames.

The optional buffer_size argument sets the number of frames stored before new incoming frames are dropped. Larger values reduce drops at the cost of RAM. The exact maximum depends on the build, but it is limited by the underlying ringbuffer implementation to roughly 100 frames.

Raises OSError if CSI cannot be enabled, for example if Wi-Fi is not active or the ESP-IDF rejects the configuration.

Example:

import network
import time

wlan = network.WLAN(network.WLAN.IF_STA)
wlan.active(True)
wlan.config(protocol=network.MODE_11B | network.MODE_11G | network.MODE_11N)
wlan.config(pm=wlan.PM_NONE)
wlan.connect("SSID", "password")

while not wlan.isconnected():
    time.sleep_ms(100)

wlan.csi_enable(buffer_size=32)
WLAN.csi_disable()

Disable CSI capture and clean up resources.

WLAN.csi_read([result])

Read a CSI frame from the buffer.

Returns: A list containing CSI frame data, or None if no frames are available.

If the optional result argument is provided, it must be a previous list returned by WLAN.csi_read(). The list will be updated in place and returned again. This reduces heap churn in busy read loops by reusing the existing list object and, when the captured frame fits, the existing CSI data bytearray.

Frame list fields (in order):

  • 0 - rssi (int): Received signal strength in dBm

  • 1 - channel (int): Wi-Fi channel number

  • 2 - mac (bytes): Source MAC address (6 bytes)

  • 3 - timestamp (int): Timestamp in microseconds

  • 4 - local_timestamp (int): Local timestamp from Wi-Fi hardware

  • 5 - data (bytearray): CSI raw data (I/Q components as int8_t values)

  • 6 - rate (int): Data rate

  • 7 - sig_mode (int): Signal mode (legacy, HT, VHT)

  • 8 - mcs (int): Modulation and Coding Scheme index

  • 9 - cwb (int): Channel bandwidth

  • 10 - smoothing (int): Smoothing applied

  • 11 - not_sounding (int): Not sounding frame

  • 12 - aggregation (int): Aggregation

  • 13 - stbc (int): STBC

  • 14 - fec_coding (int): FEC coding

  • 15 - sgi (int): Short GI

  • 16 - noise_floor (int): Background noise level in dBm

  • 17 - ampdu_cnt (int): AMPDU count

  • 18 - secondary_channel (int): Secondary channel

  • 19 - ant (int): Antenna

  • 20 - sig_len (int): Signal length

  • 21 - rx_state (int): RX state

Some metadata fields may be 0 on targets where ESP-IDF does not provide the corresponding value in the public CSI receive structure.

WLAN.csi_available()

Get the number of CSI frames available in the buffer.

WLAN.csi_dropped()

Get the number of CSI frames dropped due to buffer overflow. Frames are dropped when the buffer is full and new frames arrive faster than they can be read. Increase buffer_size in csi_enable() to reduce drops.

Constants

WLAN.PM_PERFORMANCE
WLAN.PM_POWERSAVE
WLAN.PM_NONE

Allowed values for the WLAN.config(pm=...) network interface parameter:

  • PM_PERFORMANCE: enable WiFi power management to balance power savings and WiFi performance

  • PM_POWERSAVE: enable WiFi power management with additional power savings and reduced WiFi performance

  • PM_NONE: disable wifi power management

ESP32 Protocol Constants

The following ESP32-only constants relate to the WLAN.config(protocol=...) network interface parameter:

WLAN.PROTOCOL_DEFAULT

A bitmap representing all of the default 802.11 Wi-Fi modes supported by the chip. Consult ESP-IDF Wi-Fi Protocols documentation for details.

WLAN.PROTOCOL_LR

This value corresponds to the Espressif proprietary “long-range” mode, which is not compatible with standard Wi-Fi devices. By setting this protocol it’s possible for an ESP32 STA in long-range mode to connect to an ESP32 AP in long-range mode, or to use ESP-NOW long range modes.

This mode can be bitwise ORed with some standard 802.11 protocol bits (including WLAN.PROTOCOL_DEFAULT) in order to support a mix of standard Wi-Fi modes as well as LR mode, consult the Espressif long-range documentation for more details.

Long range mode is not supported on ESP32-C2.

WLAN.BANDWIDTH_20
WLAN.BANDWIDTH_40
WLAN.BANDWIDTH_80
WLAN.BANDWIDTH_160
WLAN.BANDWIDTH_80_80

Allowed values for the WLAN.config(bandwidth=...) network interface parameter:

  • BANDWIDTH_20: specifies a 20MHz wide WiFi channel when in STA and AP mode

  • BANDWIDTH_40: specifies a 40MHz wide WiFi channel when in STA and AP mode

  • BANDWIDTH_80: specifies a 80MHz wide WiFi channel when in AP mode, may not be available on all ESP32 models

  • BANDWIDTH_160: specifies a 160MHz wide WiFi channel when in AP mode, may not be available on all ESP32 models

  • BANDWIDTH_80_80: specifies a multi-antenna 80MHz + 80MHz wide WiFi channel setup when in AP mode, may not be available on all ESP32 models.

When in STA mode, bandwidth can only be changed when the adapter is not connected to a network. In AP mode it can be changed at any time.