lwip_mqtt_freertos#
Overview#
The lwip_mqtt demo application demonstrates MQTT client connecting to MQTT broker via unsecured socket. The application obtains IP and DNS addresses from DHCP and resolves broker’s hostname if needed. Then it connects to the broker and subscribes to the “lwip_topic/#” and “lwip_other/#” topics. Further it publishes five messages to the “lwip_topic/100” which are also received back as the board is subscribed to the “lwip_topic/#”. It then disconnects from the broker.
Prepare the Demo#
Make sure the MQTT broker pointed to by EXAMPLE_MQTT_SERVER_HOST and EXAMPLE_MQTT_SERVER_PORT definitions is up and accessible on your network via unsecured socket. A public MQTT testing server can be used or you can install a broker locally and modify the definitions mentioned above.
The public testing MQTT brokers might be overloaded and unable to connect to sometimes. Better option might be to install an MQTT broker, like Eclipse Mosquitto, locally and have full control. If you install this one, the following settings added to its configuration file mosquitto.conf allow to connect from the board to the broker via port 1883 and without a username and a password (provided there are no additional restrictions, like firewall blocking the port, in place):
allow_anonymous true listener 1883
Naturally, this means that anybody able to establish TCP connection with that computer on port 1883 might connect to the broker.
Connect a USB cable between the PC host and the OpenSDA(or USB to Serial) USB port on the target board.
Open a serial terminal on PC for OpenSDA serial(or USB to Serial) device with these settings:
115200 baud rate
8 data bits
No parity
One stop bit
No flow control
Insert the Ethernet Cable into the target board’s RJ45 port and connect it to a router (or other DHCP server capable device).
Download the program to the target board.
Either press the reset button on your board or launch the debugger in your IDE to begin running the demo.
Running the demo#
When the demo runs, the log would be seen on the terminal like:
Initializing PHY...
************************************************
MQTT client example
************************************************
Getting IP address from DHCP...
IPv4 Address : 192.168.10.4
IPv4 Subnet mask : 255.255.255.0
IPv4 Gateway : 192.168.10.1
Resolving "test.mosquitto.org"...
Connecting to MQTT broker at 5.196.78.28...
MQTT client "nxp_322c480e82967d6a" connected.
Subscribing to the topic "lwip_topic/#" with QoS 0...
Subscribing to the topic "lwip_other/#" with QoS 1...
Subscribed to the topic "lwip_topic/#".
Subscribed to the topic "lwip_other/#".
Going to publish to the topic "lwip_topic/100"...
Received 18 bytes from the topic "lwip_topic/100": "message from board"
Published to the topic "lwip_topic/100".
Going to publish to the topic "lwip_topic/100"...
Received 18 bytes from the topic "lwip_topic/100": "message from board"
Published to the topic "lwip_topic/100".
Going to publish to the topic "lwip_topic/100"...
Received 18 bytes from the topic "lwip_topic/100": "message from board"
Published to the topic "lwip_topic/100".
Going to publish to the topic "lwip_topic/100"...
Received 18 bytes from the topic "lwip_topic/100": "message from board"
Published to the topic "lwip_topic/100".
Going to publish to the topic "lwip_topic/100"...
Received 18 bytes from the topic "lwip_topic/100": "message from board"
Published to the topic "lwip_topic/100".
Disconnected from MQTT broker.
Supported Boards#
EVKB-IMXRT1050
Hardware requirements
Mini/micro USB cable
Network cable RJ45 standard
EVKB-IMXRT1050 board
Personal Computer
Board settings
No special settings are required.
MIMXRT1060-EVKB
Hardware requirements
Mini/micro USB cable
MIMXRT1060-EVKB board
Personal Computer
Board settings
No special settings are required.
MIMXRT1170-EVKB
Hardware requirements
Mini/micro USB cable
Network cable RJ45 standard
MIMXRT1170-EVKB board
Personal Computer
Board settings
This example uses 1G port(J4) as default. If want to test 100M port(J3), please set the macro BOARD_NETWORK_USE_100M_ENET_PORT to 1.
MIMXRT1060-EVKC
Hardware requirements
Mini/micro USB cable
MIMXRT1060-EVKC board
Personal Computer
Board settings
No special settings are required.
FRDM-IMXRT1152
Hardware requirements
FRDM-IMXRT1152 board
USB Type-C cable
RJ45 network cable
Personal Computer
Board settings
Connect the USB Type-C cable to the FRDM-IMXRT1152 USB debug connector.
Use the Gigabit Ethernet RJ45 port (J130).
Set J134 to position 1-2 for the shared
ENET_MDIO/ETH0_RDATA3routing.
EVK-MIMXRT1020
Hardware requirements
Mini/micro USB cable
Network cable RJ45 standard
EVK-MIMXRT1020 board
Personal Computer
Board settings
No special settings are required.
Note: To debug in qspiflash, following steps are needed:
Select the flash target and compile.
Set the SW8: 1 off 2 off 3 on 4 off, then power on the board and connect USB cable to J23.
Start debugging in IDE.
Keil: Click “Download (F8)” to program the image to qspiflash first then clicking “Start/Stop Debug Session (Ctrl+F5)” to start debugging.
MIMXRT1024-EVK
Hardware requirements
Mini/micro USB cable
Network cable RJ45 standard
MIMXRT1024-EVK board
Personal Computer
Board settings
No special settings are required.
Note: To debug in qspiflash, following steps are needed:
Select the flash target and compile.
Set the SW8: 1 off 2 off 3 on 4 off, then power on the board and connect USB cable to J23.
Start debugging in IDE.
Keil: Click “Download (F8)” to program the image to qspiflash first then clicking “Start/Stop Debug Session (Ctrl+F5)” to start debugging.
MIMXRT1040-EVK
Hardware requirements
Mini/micro USB cable
MIMXRT1040-EVK board
Personal Computer
Board settings
No special settings are required.
EVK-MIMXRT1064
Hardware requirements
Mini/micro USB cable
EVK-MIMXRT1064 board
Personal Computer
Board settings
No special settings are required.
MIMXRT1160-EVK
Hardware requirements
Mini/micro USB cable
Network cable RJ45 standard
MIMXRT1160-EVK board
Personal Computer
Board settings
This example uses 1G port(J4) as default. If want to test 100M port(J3), please set the macro BOARD_NETWORK_USE_100M_ENET_PORT to 1.
MIMXRT1180-EVK
Hardware requirements
Mini/micro USB cable
Network cable RJ45 standard
MIMXRT1180-EVK board
Personal Computer
Board settings
This example uses Ethernet RJ45 port J32.
FRDM-MCXA577
Hardware requirements
Type-C USB cable
RJ45 Network cable (for 100BASE-TX mode)
10BASE-T1S network adapter and cable (optional for 10BASE-T1S mode)
FRDM-MCXA577 board
Personal Computer
Board settings
Short position 2-3 on J29.
Use with 10BASE-T1S Ethernet
The example uses 100BASE-TX Ethernet over RJ45 by default. If you want to use the internal 10BASE-T1S digital PHY, redefine BOARD_NETWORK_USE_TENBASET_PHY from board.h to 1 and rebuild. Connect to a PC with a 10BASE-T1S network adapter instead of RJ45 and enable PLCA on a PC with the following parameters: - node ID: 0 (PLCA coordinator) - node count: 8 - TO timer: 32 BT - burst count: 0 - burst timer: 128 BT
FRDM-MCXE247
Hardware requirements
USB-C cable
Network cable RJ45 standard
FRDM-MCXE247 board
Personal Computer
Board settings
No special settings are required.
FRDM-MCXN947
Hardware requirements
Type-C USB cable
RJ45 Network cable
FRDM-MCXN947 board
Personal Computer
Board settings
Connect JP13 2-3 pin. Populate R274 to sync reference clock.
FRDM-MCXN947T
Hardware requirements
Type-C USB cable
RJ45 Network cable
FRDM-MCXN947T board
Personal Computer
Board settings
Connect JP13 2-3 pin. Populate R274 to sync reference clock.
FRDM-RW612
Hardware requirements
USB-C cable
Network cable RJ45 standard
FRDM-RW612 board
Personal Computer
Board settings
Make sure SJ21 and SJ22 have positions 1 and 2 soldered (default).
LPCXpresso54628
Hardware requirements
Mini/micro USB cable
RJ45 Network cable
LPCXpresso54628 board
Router or other device with DHCP server capability
Personal Computer
Board settings
For LPCXpresso54628 V2.0:JP11 and JP12 1-2 on.
LPCXpresso54S018
Hardware requirements
Mini/micro USB cable
RJ45 Network cable
LPCXpresso54S018 board
Router or other device with DHCP server capability
Personal Computer
Board settings
LPCXpresso54S018M
Hardware requirements
Mini/micro USB cable
RJ45 Network cable
LPCXpresso54S018M board
Router or other device with DHCP server capability
Personal Computer
Board settings
For LPCXpresso54S018M V2.0:JP11, JP12, JP14 and JP15 1-2 on.
MCX-N5XX-EVK
Hardware requirements
Mini/micro USB cable
RJ45 Network cable
MCX-N5XX-EVK board
Personal Computer
Board settings
Connect JP13 2-3 pin. Populate R274 to sync reference clock.
MCX-N9XX-EVK
Hardware requirements
Mini/micro USB cable
RJ45 Network cable
MCX-N9XX-EVK board
Personal Computer
Board settings
Connect JP13 2-3 pin. Populate R274 to sync reference clock.
RD-RW612-BGA
Hardware requirements
Micro USB cable
Network cable RJ45 standard
RD-RW612-BGA board
Personal Computer
Board settings
Connect JP54. Load R520, R508, R505 Remove R518, R507, R506
FRDM-IMXRT1186
Hardware requirements
Type-C USB cable
Network cable RJ45 standard
FRDM-IMXRT1186 board
Personal Computer
Board settings
Short jumpers J12 (1-2) and J13 (2-3) and connect network cable to J56A.