Introduction

PHYTEC's WLAN adapter, PEB-WLBT-05, is aimed to support your processor with WiFi and Bluetooth. In this guide, we will explain how to connect and install the WLAN adapter on the phyBOARD-Pollux.

For each kit, there are  4 variants depending on the frequency of WiFi and antenna type

There are two WiFi variants:

• IEEE 802.11 b/g/n which supports 2.4 GHz
• IEEE 802.11 b/g/n/ac which supports 2.5 and  5Ghz

There are two antenna variants:

• Chip antenna
• U.FL connector instead of an antenna (enables external antenna)

The Bluetooth is delivered via a UART interface, and it requires all 4 lines of UART (CTS, RTS, TX, RX). The WiFi is delivered via SDIO Interface, and it requires (SDIO-CLK, CMD, D0, D1, D2, D3).

Specifications

The WLAN Adapter supports the phyBOARD-Pollux kit with WiFi and Bluetooth and has the following variants depending on the frequency and antenna configuration:

• PEB-WLBT-05-22C
  
  • IEEE 802.11 b/g/n which supports 2.4 GHz, via Sterling-LWB chip
  • Mounted Chip Antenna
  • Bluetooth v4.2 BR /DR/LE
• PEB-WLBT-05-22E
  • IEEE 802.11 b/g/n which supports 2.4 GHz, via Sterling-LWB chip
  • Mounted U.FL connector instead of Antenna
  • Bluetooth v4.2 BR /DR/LE
• PEB-WLBT-05-25C
  • IEEE 802.11 b/g/n/ac which supports 2.5GHz and 5 GHz, via Sterling-LWB5 chip
  • Mounted Chip Antenna
  • Bluetooth 2.1+EDR, Bluetooth 3.0, Bluetooth 4.2 (Bluetooth Low Energy)
• PEB-WLBT-05-25E
  • IEEE 802.11 b/g/n/ac which supports 2.5GHz and 5 GHz, via Sterling-LWB5 chip
  • Mounted U.FL connector instead of Antenna
  • Bluetooth 2.1+EDR, Bluetooth 3.0, Bluetooth 4.2 (Bluetooth Low Energy)

WiFi: The WiFi is conveyed by the SD1 interface of the i.MX 8M Plus processor which is held internally from X6.

Bluetooth: The Bluetooth signal is conveyed to the processor using UART3 ( CTS, RTS, TX, RX) via X6 internally.

Hardware Installation

Step 1:  Attach the PEB-WLBT-05 to the phyBOARD-Pollux at the Expansion Connector (X6). Note the position of Pin 1 on both the PEB-WLBT-05 and phyBOARD-Pollux:

Connecting PEB-WLBT-05 to phyBOARD-Pollux

phyBOARD-Pollux with PEB-WLBT-05 (Outlined) (Top view)

phyBOARD-Pollux with PEB-WLBT-05 (connection outlined) (Side view)

Software Installation

target$ vi /boot/bootenv.txt

overlays=imx8mp-phyboard-pollux-peb-av-010.dtbo imx8mp-phyboard-pollux-peb-wlbt-05.dtbo

target$ reboot

WLAN

Changing the Wireless Network Configuration

Connecting to a WLAN Network

• First set the correct regulatory domain for your country:

target$ iw reg set DE
target$ iw reg get

You will see:

country DE: DFS-ETSI
   (2400 - 2483 @ 40), (N/A, 20), (N/A)
   (5150 - 5250 @ 80), (N/A, 20), (N/A), NO-OUTDOOR
   (5250 - 5350 @ 80), (N/A, 20), (0 ms), NO-OUTDOOR, DFS
   (5470 - 5725 @ 160), (N/A, 26), (0 ms), DFS
   (57000 - 66000 @ 2160), (N/A, 40), (N/A)

• Set up the wireless interface:

target$ ip link    # list all interfaces. Search for wlan*
target$ ip link set up dev wlan0

• Now you can scan for available networks:

target$ iw wlan0 scan | grep SSID

You can use a cross-platform supplicant with support for WEP, WPA, and WPA2 called wpa_supplicant for an encrypted connection.

• To do so, add the network-credentials to the file /etc/wpa_supplicant.conf:

country=DE
network={
    ssid="<SSID>"
    proto=WPA2
    psk="<KEY>"
}

• Now a connection can be established:

target$ wpa_supplicant -Dnl80211 -c/etc/wpa_supplicant.conf -iwlan0 -B

This should result in the following output:

...
ENT-CONNECTED - Connection to 88:33:14:5d:db:b1 completed [id=0 id_str=]

To finish the configuration you can configure DHCP to receive an IP address (supported by most WLAN access points). For other possible IP configurations, see section Changing the Network Configuration.

• First, create the directory:

target$ mkdir -p /etc/systemd/network/

• Then add the following configuration snippet in /etc/systemd/network/10-wlan0.network:

# file /etc/systemd/network/10-wlan0.network
[Match]
Name=wlan0

[Network]
DHCP=yes

• Now, restart the network daemon so that the configuration takes effect:

target$ systemctl restart systemd-networkd

Bluetooth

Bluetooth is connected with UART2 interface. More information about the module can be found at https://connectivity-staging.s3.us-east-2.amazonaws.com/2019-09/CS-DS-SterlingLWB%20v7_2.pdf. The Bluetooth device needs to be set up manually:

target$ hciconfig hci0 up
 
target$ hciconfig 
hci0:   Type: Primary  Bus: UART
        BD Address: AA:AA:AA:AA:AA:AA  ACL MTU: 1021:8  SCO MTU: 64:1
        UP RUNNING 
        RX bytes:1051 acl:0 sco:0 events:50 errors:0
        TX bytes:1291 acl:0 sco:0 commands:50 errors:0   

target$ hciconfig -a
hci0:   Type: Primary  Bus: UART
        BD Address: AA:AA:AA:AA:AA:AA  ACL MTU: 1021:8  SCO MTU: 64:1
        UP RUNNING 
        RX bytes:1051 acl:0 sco:0 events:50 errors:0
        TX bytes:1291 acl:0 sco:0 commands:50 errors:0
        Features: 0xbf 0xfe 0xcf 0xfe 0xdb 0xff 0x7b 0x87
        Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3 
        Link policy: RSWITCH SNIFF 
        Link mode: SLAVE ACCEPT 
        Name: 'BlueZ 5.50'
        Class: 0x000000
        Service Classes: Unspecified
        Device Class: Miscellaneous, 
        HCI Version: 4.1 (0x7)  Revision: 0x0
        LMP Version: 4.1 (0x7)  Subversion: 0x2209
        Manufacturer: Broadcom Corporation (15)

Now you can scan your environment for visible Bluetooth devices. Bluetooth is not visible during a default startup.

target$ hcitool scan
Scanning ...
       XX:XX:XX:XX:XX:XX       <SSID>

Visibility

To activate visibility:

target$ hciconfig hci0 piscan

To disable visibility:

target$ hciconfig hci0 noscan

Connecting via bluetoothd

target$ bluetoothctl
[bluetooth]# discoverable on
Changing discoverable on succeeded
[bluetooth]# pairable on
Changing pairable on succeeded
[bluetooth]# agent on
Agent registered
[bluetooth]# default-agent 
Default agent request successful
[bluetooth]# scan on
[NEW] Device XX:XX:XX:XX:XX:XX <name>
[bluetooth]# connect XX:XX:XX:XX:XX:XX