FETMX6ULL-C system on module(SoM) is based on NXP low power featuring processor i.MX6ULL, Cortex-A7@800MHz. Native support: 8 serial ports, 2 Ethernet ports, 2 CAN controller, 2 USB 2.0, LCD, etc. Ultra-Small size design, only 40*29mm, Suitable for application scenarios with a limited volume.

To facilitate user to test the performance and functions of FETMX6ULL-C SoM, Forlinx provides a development board, OKMX6ULL-C SBC. The function interfaces commonly used in the product development process are drawn out, such as 2-ch Ethernet, 2-ch USB, 2-ch CAN, 4-ch UART, 2-ch SPI and 2-ch IIC. Also reserved LCD interface for display and slots for 4G module and WiFi module.

This article introduces the interface function and test method of Forlinx iMX6ULL development board(OKMX6ULL-C SBC), helps user quickly familiar with it. Describes the test method of WiFi, and how to troubleshoot some problems during use. During the test, some commands were annotated to facilitate users' understanding.

First, WiFi Test of Forlinx iMX6ULL developemnt board (OKMX6ULL-C SBC)

WiFi Support

Module	Support
RTL8188EUS	WiFi
RTL8723BU	WiFi
RTL8723DU	WiFi

1. USB WiFi RTL8188eus

Note: USB WiFi wireless LAN card is an optional module(For optional module, you can visit the module part of Forlinx official web)

The following test is in STA mode, connecting WiFi module to a wireless network :

Step 1: Power on iMX6ULL development board and start Linux system.

Step 2: Connect USB WiFi to USB Host interface of Forlinx iMX6ULL development board

Step 3: Enter the corresponding parameters as the following format:

-i : WiFi model;

-s: name of WiFi hotspot;

-p: password. If no password, enter -p NONE;

The router uses wpa encryption. For specific operation instructions,please check WiFi.sh.

Connect and input as follows:

root@fl-imx6ull:~# fltest_cmd_WiFi.sh -i 8188 -s forlinx -p xxxx

The output information is as follows:

wifi 8188

ssid forlinx

pasw xxxx

usbcore: deregistering interface driver rtl8723bu

RTL871X: module exit start

usbcore: deregistering interface driver rtl8188eu

RTL871X: rtw_ndev_uninit(wlan1)

usb 1-1.3: reset high-speed USB device number 7 using ci_hdrc

RTL871X: module exit success

RTL871X: module init start

RTL871X: rtl8188eu v4.3.0.9_15178.20150907

RTL871X: build time: Mar 25 2020 02:23:46

bFWReady == _FALSE call reset 8051...

RTL871X: rtw_ndev_init(wlan0)

usbcore: registered new interface driver rtl8188eu

RTL871X: module init ret=0

==> rtl8188e_iol_efuse_patch

IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready

ps: invalid option -- 'f'

BusyBox v1.24.1 (2019-04-27 02:24:01 CST) multi-call binary.

Usage: ps

Successfully initialized wpa_supplicant

rfkill: Cannot open RFKILL controRTL871X: set bssid:00:00:00:00:00:00

l device

RTL871X: set ssid [g▒isQ▒J▒)ͺ▒▒▒▒F|▒T▒▒vZ.c3▒ɚ���<▒▒▒▒] fw_state=0x00000008

ioctl[SIOCSIWAP]: Operation not permitted

ioctl[SIOCGIWSCAN]: Resource temporarily unavailable

ioctl[SIOCGIWSCAN]: Resource temporarily unavailable

RTL871X: indicate disassoc

wlan0: Trying to associate with 04:d7:a5:84:fa:40 (SSID='forlinx' freq=2437 MHz)

RTL871X: set ssid [forlinx] fw_state=0x00000008

RTL871X: set bssid:04:d7:a5:84:fa:40

RTL871X: start auth

RTL871X: auth success, start assoc

RTL871X: assoc success

IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready

RTL871X: recv eapol packet

wlan0: Associated with 04:d7:a5:84:fa:40

RTL871X: send eapol packet

RsvdPageNum: 8

udhcpc (v1.24.1) started

RTL871X: recv eapol packet

RTL871X: send eapol packet

RTL871X: recv eapol packet

RTL871X: send eapol packet

RTL871X: set pairwise key camid:4, addr:04:d7:a5:84:fa:40, kid:0, type:AES

wlan0: WPA: Key negotiation completed with 04:d7:a5:84:fa:40 [PTKRTL871X: set group key camid:5, addr:04:d7:a5:84:fa:40, kid:2, type:AES

=CCMP GTK=CCMP]

wlan0: CTRL-EVENT-CONNECTED - Connection to 04:d7:a5:84:fa:40 completed [id=0 id_str=]

Sending discover...

Sending select for 192.168.4.129...

Lease of 192.168.4.129 obtained, lease time 36000

/etc/udhcpc.d/50default: Adding DNS 222.222.202.202

/etc/udhcpc.d/50default: Adding DNS 222.222.222.222

Finshed!

After the script running finished, if it automatically assigns IP and adds DNS, then WiFi connection is successful.

Step 5: Ping ip or domain name, the command is as follows.

root@fl-imx6ull:~# ping -c 4 www.baidu.com

PING www.baidu.com (220.181.38.149): 56 data bytes

64 bytes from 220.181.38.149: seq=0 ttl=51 time=26.648 ms

64 bytes from 220.181.38.149: seq=1 ttl=51 time=13.529 ms

64 bytes from 220.181.38.149: seq=2 ttl=51 time=15.656 ms

64 bytes from 220.181.38.149: seq=3 ttl=51 time=26.249 ms

--- www.baidu.com ping statistics ---

4 packets transmitted, 4 packets received, 0% packet loss

round-trip min/avg/max = 13.529/20.520/26.648 ms

Step 6: Uninstall the modules that have been added to the kernel.

root@fl-imx6ull:~# rmmod 8188eu

The output information is as follows:

RTL871X: module exit start

usbcore: deregistering interface driver rtl8188eu

RTL871X: indicate disassoc

RTL871X: rtw_cmd_thread: DriverStopped(1) SurpriseRemoved(0) break at line 478

wlan0: CTRL-EVENT-DISCONNECTED bssid=04:d7:a5:84:fa:40 reason=3 locally_generated=1

RTL871X: rtw_ndev_uninit(wlan0)

RTL871X: rtw_dev_unload: driver not in IPS

usb 1-1.3: reset high-speed USB device number 7 using ci_hdrc

RTL871X: module exit success

2. Carrier Board WIFI

Note:

l WiFi frequency: 2.4G

l Compatible with two WiFi drivers: 8723bu, 8723du

l The router uses wpa encryption by default.

If the development board has an onboard WiFi wireless LAN card, it will soldered on the evaluation board as shown in the below picture (the picture is 8723du):

Step 1: Check whether the module has been soldered on iMX6ULL development board, and the correct soldering is as shown in above picture. And connect the antenna.

Step 2: Power on iMX6ULL development board, start Linux system, and use lsmod to check the module loading status first:

root@fl-imx6ull:~# lsmod

Module                          Size Used by

mx6s_capture               14876 0

8723 du                         1313893 0      //The default wifi is automatically loaded, and 8723du has been loaded successfully

ov9650_camera             12446 0

Note: If 8723 b u is soldered on Forlinx iMX6ULL development board, using lsmod will display 8723 b u

The following takes 8723du as an example to test:

Step 3: Test

Ø STA mode

In this mode, connect to the wireless network as a station. The operation method is as follows:

-i: WiFi model; -s: name of WiFi hotspot; -p: password, if no password, enter -p NONE; The router uses wpa encryption. For specific operation instructions,please check WiFi.sh.

root@fl-imx6ull:~# fltest_cmd_wifi.sh -i 8723du -s forlinx -p xxx       //Execute the test script

The output information is as follows:

wifi 8723du

ssid forlinx

pasw xxx

usbcore: deregistering interface driver rtl8723du

usbcore: registered new interface driver rtl8723du

IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready

Successfully initialized wpa_supplicant

rfkill: Cannot open RFKILL control device

udhcpc (v1.24.1) started

Sending discover...

wlan0: CTRL-EVENT-REGDOM-CHANGE init=BEACON_HINT type=UNKNOWN

wlan0: Trying to associate with 04:d7:a5:f9:26:1d (SSID='forlinx' freq=2427 MHz)

wlan0: Associated with 04:d7:a5:f9:26:1d

IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready

wlan0: WPA: Key negotiation completed with 04:d7:a5:f9:26:1d [PTK=CCMP GTK=TKIP]

wlan0: CTRL-EVENT-CONNECTED - Connection to 04:d7:a5:f9:26:1d completed [id=0 id_str=]

nf_conntrack: automatic helper assignment is deprecated and it will be removed soon. Use the iptables CT target to attach helpers instead.

Sending discover...

Sending select for 192.168.5.186...

Lease of 192.168.5.186 obtained, lease time 1800

/etc/udhcpc.d/50default: Adding DNS 222.222.202.202

/etc/udhcpc.d/50default: Adding DNS 222.222.222.222

WLAN Finshed!

After the script running finished, if it automatically assigns IP and adds DNS, then WiFi connection is successful.

Ping ip or domain name, the command is as follows

root@fl-imx6ull:~# ping -c 5 www.baidu.com

The output information is as follows:

PING 192.168.4.1 (192.168.4.1): 56 data bytes

64 bytes from 192.168.4.1: seq=0 ttl=128 time=39.783 ms

64 bytes from 192.168.4.1: seq=1 ttl=128 time=81.529 ms

64 bytes from 192.168.4.1: seq=2 ttl=128 time=15.236 ms

64 bytes from 192.168.4.1: seq=3 ttl=128 time=12.076 ms

64 bytes from 192.168.4.1: seq=4 ttl=128 time=16.300 ms

--- 192.168.4.1 ping statistics ---

5 packets transmitted, 5 packets received, 0% packet loss

round-trip min/avg/max = 12.076/32.984/81.529 ms

WiFi signal

Check WiFi signal as follows:

root@fl-imx6ull:~# cat /proc/net/wireless | grep wlan0 | awk '{print $3}' //Get signal strength

78.

root@fl-imx6ull:~# cat /proc/net/wireless | grep wlan0 | awk '{print $4}' //Get signal quality, dBm

-68.

root@fl-imx6ull:~# cat /proc/net/wireless | grep wlan0 | awk '{print $5}' //The background noise of the network port, dBm

-256.

AP mode

Note:

l This module supports AP mode, and the theoretical maximum number of connected users is 8.

l This example is the description of Ethernet eth0 connecting to the router. After the configuration of Ethernet, it need to test whether eth0 can connect to Internet. If it can connect to Internet (please refer to "Wired Network Card" chapter for the method), please continue to follow the operation steps. If not, please check whether the connection of Ethernet or router is normal.

In AP mode, devices such as mobile phones can directly connect to the module.

Set Ethernet IP, configure network firewall:

root@fl-imx6ull:~# udhcpc -i eth0     //Automatically assign IP, if eth0 network has been tested to be normal, you can skip this step

root@fl-imx6ull:~# echo 1 > /proc/sys/net/ipv4/ip_forward    //Open IP forwarding

root@fl-imx6ull:~# iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE     //Set forwarding rules

Set WiFi mode and IP

Make sure module 8723bu is loaded.

root@fl-imx6ull:~# ifconfig wlan0 up    //Turn on WiFi

root@fl-imx6ull:~# ifconfig wlan0 192.168.0.10 netmask 255.255.255.0    //Set IP and subnet mask

root@fl-imx6ull:~# ifconfig wlan0 promisc     //Set wlan0 to promiscuous mode

enable AP

root@fl-imx6ull:~# udhcpd /etc/udhcpd/udhcpd.conf &          //Configuration information such as WiFi address and gateway

root@fl-imx6ull:~# hostapd -d /etc/hostapd/hostapd.conf &      //Encryption method, username, password and other settings

In hostapd.conf file: ssid is username, / is password

Mobile terminals such as mobile phones can connect to the AP hotspot of development board through WiFi. Forlinx iMX6ULL development board uses the following username and password by default:

Hotspot name: forlinxtest Password: 1234567890

Step 4: Uninstall the modules that have been added to the kernel:

root@fl-imx6ull:~# rmmod 8723du

usbcore: deregistering interface driver rtl8723du

wlan0: CTRL-EVENT-DISCONNECTED bssid=04:d7:a5:f9:26:1d reason=0

FETMX6ULL-C SoM is the third SoM launched by Forlinx based on NXP i.MX6U series processors. With Forlinx matured technical solutions, it bring a whole new experience of stable and reliable. Compact size by 40*29mm while the package is 2mm height board to board connector. It combines small size and easy disassembly. Welcome send an inquiry for details.