esp-idf/examples/protocols/mqtt/tcp/README.md

Supported Targets	ESP32	ESP32-C2	ESP32-C3	ESP32-C6	ESP32-H2	ESP32-S2	ESP32-S3

ESP-MQTT sample application

(See the README.md file in the upper level 'examples' directory for more information about examples.)

This example connects to the broker URI selected using idf.py menuconfig (using mqtt tcp transport) and as a demonstration subscribes/unsubscribes and send a message on certain topic. (Please note that the public broker is maintained by the community so may not be always available, for details please see this disclaimer)

Note: If the URI equals FROM_STDIN then the broker address is read from stdin upon application startup (used for testing)

It uses ESP-MQTT library which implements mqtt client to connect to mqtt broker.

How to use example

Hardware Required

This example can be executed on any ESP32 board, the only required interface is WiFi and connection to internet.

Configure the project

• Open the project configuration menu (idf.py menuconfig)
• Configure Wi-Fi or Ethernet under "Example Connection Configuration" menu. See "Establishing Wi-Fi or Ethernet Connection" section in examples/protocols/README.md for more details.

Build and Flash

Build the project and flash it to the board, then run monitor tool to view serial output:

idf.py -p PORT flash monitor

(To exit the serial monitor, type Ctrl-].)

See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.

Example Output

I (3714) event: sta ip: 192.168.0.139, mask: 255.255.255.0, gw: 192.168.0.2
I (3714) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE
I (3964) MQTT_CLIENT: Sending MQTT CONNECT message, type: 1, id: 0000
I (4164) MQTT_EXAMPLE: MQTT_EVENT_CONNECTED
I (4174) MQTT_EXAMPLE: sent publish successful, msg_id=41464
I (4174) MQTT_EXAMPLE: sent subscribe successful, msg_id=17886
I (4174) MQTT_EXAMPLE: sent subscribe successful, msg_id=42970
I (4184) MQTT_EXAMPLE: sent unsubscribe successful, msg_id=50241
I (4314) MQTT_EXAMPLE: MQTT_EVENT_PUBLISHED, msg_id=41464
I (4484) MQTT_EXAMPLE: MQTT_EVENT_SUBSCRIBED, msg_id=17886
I (4484) MQTT_EXAMPLE: sent publish successful, msg_id=0
I (4684) MQTT_EXAMPLE: MQTT_EVENT_SUBSCRIBED, msg_id=42970
I (4684) MQTT_EXAMPLE: sent publish successful, msg_id=0
I (4884) MQTT_CLIENT: deliver_publish, message_length_read=19, message_length=19
I (4884) MQTT_EXAMPLE: MQTT_EVENT_DATA
TOPIC=/topic/qos0
DATA=data
I (5194) MQTT_CLIENT: deliver_publish, message_length_read=19, message_length=19
I (5194) MQTT_EXAMPLE: MQTT_EVENT_DATA
TOPIC=/topic/qos0
DATA=data

Using Wi-Fi connection with ESP32P4

It is possible to use Wi-Fi connection on targets that do not support native Wi-Fi peripheral. This example demonstrates using esp_wifi_remote on ESP32P4 in the test configuration defined as sdkconfig.ci.p4_wifi. This configuration requires another ESP target with native Wi-Fi support physically connected to the ESP32-P4.

Configure master-slave verification

In order to secure the physical connection between the ESP32-P4 (master) and the slave device, it is necessary to set certificates and keys for each side. To bootstrap this step, you can use one-time generated self-signed RSA keys and certificates running:

./managed_components/espressif__esp_wifi_remote/examples/test_certs/generate_test_certs.sh espressif.local

Configure the slave project

It is recommended to create a new project from esp_wifi_remote component's example with

idf.py create-project-from-example "espressif/esp_wifi_remote:server"

but you can also build and flash the slave project directly from the managed_components directory using:

idf.py -C managed_components/espressif__esp_wifi_remote/examples/server/ -B build_slave 

Please follow these steps to setup the slave application:

• idf.py set-target -- choose the slave target (must support Wi-Fi)
• idf.py menuconfig -- configure the physical connection and verification details:
  • CONFIG_ESP_WIFI_REMOTE_EPPP_CLIENT_CA -- CA for verifying ESP32-P4 application
  • CONFIG_ESP_WIFI_REMOTE_EPPP_SERVER_CRT -- slave's certificate
  • CONFIG_ESP_WIFI_REMOTE_EPPP_SERVER_KEY -- slave's private key
• idf.py build flash monitor

Configure the master project (ESP32-P4)

similarly to the slave project, we have to configure

• the physical connection
• the verification
  • CONFIG_ESP_WIFI_REMOTE_EPPP_SERVER_CA -- CA for verifying the slave application
  • CONFIG_ESP_WIFI_REMOTE_EPPP_CLIENT_CRT -- our own certificate
  • CONFIG_ESP_WIFI_REMOTE_EPPP_CLIENT_KEY -- our own private key

After project configuration, you build and flash the board with

idf.py build flash monitor

Example Output of the slave device

I (7982) main_task: Returned from app_main()
I (8242) rpc_server: Received header id 2
I (8242) pp: pp rom version: 5b8dcfa
I (8242) net80211: net80211 rom version: 5b8dcfa
I (8252) wifi:wifi driver task: 4082be8c, prio:23, stack:6656, core=0
I (8252) wifi:wifi firmware version: feaf82d
I (8252) wifi:wifi certification version: v7.0
I (8252) wifi:config NVS flash: enabled
I (8262) wifi:config nano formatting: disabled
I (8262) wifi:mac_version:HAL_MAC_ESP32AX_761,ut_version:N, band:0x1
I (8272) wifi:Init data frame dynamic rx buffer num: 32
I (8272) wifi:Init static rx mgmt buffer num: 5
I (8282) wifi:Init management short buffer num: 32
I (8282) wifi:Init dynamic tx buffer num: 32
I (8292) wifi:Init static tx FG buffer num: 2
I (8292) wifi:Init static rx buffer size: 1700 (rxctrl:92, csi:512)
I (8302) wifi:Init static rx buffer num: 10
I (8302) wifi:Init dynamic rx buffer num: 32
I (8302) wifi_init: rx ba win: 6
I (8312) wifi_init: accept mbox: 6
I (8312) wifi_init: tcpip mbox: 32
I (8322) wifi_init: udp mbox: 6
I (8322) wifi_init: tcp mbox: 6
I (8322) wifi_init: tcp tx win: 5760
I (8332) wifi_init: tcp rx win: 5760
I (8332) wifi_init: tcp mss: 1440
I (8342) wifi_init: WiFi IRAM OP enabled
I (8342) wifi_init: WiFi RX IRAM OP enabled
I (8352) wifi_init: WiFi SLP IRAM OP enabled
I (8362) rpc_server: Received header id 11
I (8362) rpc_server: Received header id 4
I (8372) rpc_server: Received header id 6
I (8372) phy_init: phy_version 270,339aa07,Apr  3 2024,16:36:11
I (8492) wifi:enable tsf
I (8492) rpc_server: Received WIFI event 41
I (8502) rpc_server: Received WIFI event 2
I (8732) rpc_server: Received header id 10
I (8742) rpc_server: Received header id 5
I (8752) rpc_server: Received header id 8
I (11452) wifi:new:<6,0>, old:<1,0>, ap:<255,255>, sta:<6,0>, prof:1, snd_ch_cfg:0x0
I (11452) wifi:(connect)dot11_authmode:0x3, pairwise_cipher:0x3, group_cipher:0x1
I (11452) wifi:state: init -> auth (0xb0)
I (11462) rpc_server: Received WIFI event 41
I (11462) wifi:state: auth -> assoc (0x0)
I (11472) wifi:(assoc)RESP, Extended Capabilities length:8, operating_mode_notification:0
I (11472) wifi:(assoc)RESP, Extended Capabilities, MBSSID:0, TWT Responder:0, OBSS Narrow Bandwidth RU In OFDMA Tolerance:0
I (11482) wifi:Extended Capabilities length:8, operating_mode_notification:1
I (11492) wifi:state: assoc -> run (0x10)
I (11492) wifi:(trc)phytype:CBW20-SGI, snr:50, maxRate:144, highestRateIdx:0
W (11502) wifi:(trc)band:2G, phymode:3, highestRateIdx:0, lowestRateIdx:11, dataSchedTableSize:14
I (11512) wifi:(trc)band:2G, rate(S-MCS7, rateIdx:0), ampdu(rate:S-MCS7, schedIdx(0, stop:8)), snr:50, ampduState:wait operational
I (11522) wifi:ifidx:0, rssi:-45, nf:-95, phytype(0x3, CBW20-SGI), phymode(0x3, 11bgn), max_rate:144, he:0, vht:0, ht:1
I (11532) wifi:(ht)max.RxAMPDULenExponent:3(65535 bytes), MMSS:6(8 us)
W (11542) wifi:<ba-add>idx:0, ifx:0, tid:0, TAHI:0x1002cb4, TALO:0x1b942980, (ssn:0, win:64, cur_ssn:0), CONF:0xc0000005
I (11572) wifi:connected with Cermakowifi, aid = 2, channel 6, BW20, bssid = 80:29:94:1b:b4:2c
I (11572) wifi:cipher(pairwise:0x3, group:0x1), pmf:0, security:WPA2-PSK, phy:11bgn, rssi:-45
I (11582) wifi:pm start, type: 1, twt_start:0

I (11582) wifi:pm start, type:1, aid:0x2, trans-BSSID:80:29:94:1b:b4:2c, BSSID[5]:0x2c, mbssid(max-indicator:0, index:0), he:0
I (11592) wifi:dp: 1, bi: 102400, li: 3, scale listen interval from 307200 us to 307200 us
I (11602) wifi:set rx beacon pti, rx_bcn_pti: 10, bcn_timeout: 25000, mt_pti: 10, mt_time: 10000
I (11612) wifi:[ADDBA]TX addba request, tid:0, dialogtoken:1, bufsize:64, A-MSDU:0(not supported), policy:1(IMR), ssn:0(0x0)
I (11622) wifi:[ADDBA]TX addba request, tid:7, dialogtoken:2, bufsize:64, A-MSDU:0(not supported), policy:1(IMR), ssn:0(0x20)
I (11632) wifi:[ADDBA]TX addba request, tid:5, dialogtoken:3, bufsize:64, A-MSDU:0(not supported), policy:1(IMR), ssn:0(0x0)
I (11642) wifi:[ADDBA]RX addba response, status:0, tid:7/tb:0(0x1), bufsize:64, batimeout:0, txa_wnd:64
I (11652) wifi:[ADDBA]RX addba response, status:0, tid:5/tb:0(0x1), bufsize:64, batimeout:0, txa_wnd:64
I (11662) wifi:[ADDBA]RX addba response, status:0, tid:0/tb:1(0x1), bufsize:64, batimeout:0, txa_wnd:64
I (11672) wifi:AP's beacon interval = 102400 us, DTIM period = 1
I (11682) rpc_server: Received WIFI event 4
I (15682) esp_netif_handlers: sta ip: 192.168.0.33, mask: 255.255.255.0, gw: 192.168.0.1
I (15682) rpc_server: Received IP event 0
I (15682) rpc_server: Main DNS:185.162.24.55
I (15682) rpc_server: IP address:192.168.0.33

Example Output of the master device (ESP32-P4)

I (445) example_connect: Start example_connect.
I (455) uart: queue free spaces: 16
I (455) eppp_link: Waiting for IP address 0
I (3195) esp-netif_lwip-ppp: Connected
I (3195) eppp_link: Got IPv4 event: Interface "pppos_client(EPPP0)" address: 192.168.11.2
I (3195) esp-netif_lwip-ppp: Connected
I (3195) eppp_link: Connected! 0
I (5475) example_connect: Waiting for IP(s)
I (8405) esp_wifi_remote: esp_wifi_internal_reg_rxcb: sta: 0x4001c68a
I (9445) example_connect: Got IPv6 event: Interface "pppos_client" address: fe80:0000:0000:0000:5632:04ff:fe08:5054, type: ESP_IP6_ADDR_IS_LINK_LOCAL
I (12415) rpc_client: Main DNS:185.162.24.55
I (12415) esp_netif_handlers: pppos_client ip: 192.168.11.2, mask: 255.255.255.255, gw: 192.168.11.1
I (12415) rpc_client: EPPP IP:192.168.11.1
I (12415) example_connect: Got IPv4 event: Interface "pppos_client" address: 192.168.11.2
I (12425) rpc_client: WIFI IP:192.168.0.33
I (12435) example_common: Connected to pppos_client
I (12445) rpc_client: WIFI GW:192.168.0.1
I (12455) example_common: - IPv6 address: fe80:0000:0000:0000:5632:04ff:fe08:5054, type: ESP_IP6_ADDR_IS_LINK_LOCAL
I (12455) rpc_client: WIFI mask:255.255.255.0
I (12465) example_common: Connected to pppos_client
I (12475) example_common: - IPv4 address: 192.168.11.2,
I (12475) example_common: - IPv6 address: fe80:0000:0000:0000:5c3b:1291:05ca:6dc8, type: ESP_IP6_ADDR_IS_LINK_LOCAL
I (12495) mqtt_example: Other event id:7
I (12495) main_task: Returned from app_main()
I (12905) mqtt_example: MQTT_EVENT_CONNECTED
I (12905) mqtt_example: sent publish successful, msg_id=36013
I (12905) mqtt_example: sent subscribe successful, msg_id=44233
I (12905) mqtt_example: sent subscribe successful, msg_id=36633
I (12915) mqtt_example: sent unsubscribe successful, msg_id=15480
I (13115) mqtt_example: MQTT_EVENT_PUBLISHED, msg_id=36013
I (13415) mqtt_example: MQTT_EVENT_SUBSCRIBED, msg_id=44233
I (13415) mqtt_example: sent publish successful, msg_id=0
I (13415) mqtt_example: MQTT_EVENT_SUBSCRIBED, msg_id=36633
I (13415) mqtt_example: sent publish successful, msg_id=0
I (13425) mqtt_example: MQTT_EVENT_DATA
TOPIC=/topic/qos1
DATA=data_3
I (13435) mqtt_example: MQTT_EVENT_UNSUBSCRIBED, msg_id=15480
I (13615) mqtt_example: MQTT_EVENT_DATA
TOPIC=/topic/qos0
DATA=data
I (13925) mqtt_example: MQTT_EVENT_DATA
TOPIC=/topic/qos0