usb_cdc_4g_module

Example of the component espressif/iot_usbh_modem v1.1.2

USB CDC 4G Module

This example demonstrates the ESP32-S2, ESP32-S3 series SoC as a USB host to dial-up 4G Cat.1 through PPP to access the Internet, with the help of ESP32-SX Wi-Fi softAP function, share the Internet with IoT devices or mobile devices. Realize low-cost "medium-high-speed" Internet access.It is also equipped with a router management interface, which allows you to configure the router online and view the information of connected devices.

In addition, the ESP32-P4 supports the 4G Cat.4 module (EC20) with faster speeds, but it currently only supports internet access for itself.

Features Supported:

  • USB CDC host communication
  • Compatible with mainstream 4G module AT commands
  • PPP dial-up
  • Wi-Fi hotspot
  • 4G module status management
  • Router management interface
  • Status led indicator

ESP32-S2_USB_4g_moudle

Hardware requirement

Supported ESP Soc:

  • ESP32-S2
  • ESP32-S3
  • ESP32-P4

We recommend using ESP modules or chips that integrate 4MB above Flash, and 2MB above PSRAM. The example does not enable PSRAM by default, but users can add to tests by themselves. In theory, increasing the Wi-Fi buffer size can increase the average data throughput rate.

Hardware wiring:

Default GPIO as follows:

Functions GPIO Notes
USB D+ (green) 20 Necessary
USB D- (white) 19 Necessary
GND (black) GND Necessary
+5V (red) +5V Necessary
Modem Power Control 12 Not Necessary
Modem Reset Control 13 Necessary
System Status LED (red) 15 Not Necessary
Wi-Fi Status LED (blue) 17 Not Necessary
Modem Status LED (green) 16 Not Necessary

User can change GPIO in menuconfig -> 4G Modem Configuration -> gpio config

User Guide

Wi-Fi SSID and Password:

User can modify SSID and Password in menuconfig -> 4G Modem Configuration -> WiFi soft AP

  1. Default Wi-Fi: esp_4g_router
  2. Default Password: 12345678

LED Indicator Status:

Indicator Blink Status
System (Red) extinguish NA
quick blink restart 4G Modem
solid internal error(check SIM card please)
Wi-Fi (Blue) extinguish NA
slow blink waiting for device connection
solid device connected
Modem (Green) extinguish NA
slow blink waiting for internet connection
solid internet connected

Router management interface You can configure whether to open the router management interface in 4G Modem Configuration → Web router config of menuconfig, and change the login account and password of the router management interface.

  1. The default login account is esp32.
  2. The default password is 12345678.
  3. Search 192.168.4.1 on the webpage to enter the router background
  4. Currently supported features.
    • Support account login authentication
    • Support modify hotspot name, password, invisible or not, channel, bandwidth, security mode
    • Support to view the current connected device information, note the host name, a key to kick out the device
    • Support to view the network status and network time of the device

How to build example

You can also download then burn the firmware we have build. Download address: https://esp32.com/viewtopic.php?f=22&t=24468

  1. Confirm that the ESP-IDF environment is successfully set up, and switch to the release/v4.4 branch

  2. Add the ESP-IDF environment variable, the Linux method is as follows, other platforms please refer Set up the environment variables

    Bash

    . $HOME/esp/esp-idf/export.sh

  3. Set the IDF build target to esp32s2 or esp32s3

    Bash

    idf.py set-target esp32s2

  4. Select the Cat.1 module model Menuconfig → Component config → ESP-MODEM → Choose Modem Board, if the your module is not in the list, please refer to Other 4G Cat.1 Module Adaptation Methods to configure.

choose_modem

  1. Build, download, check log output

    Bash

    idf.py build flash monitor

Log

Plaintext

I (9654) USB_HCDC: CDC Device Connected
I (9659) esp-modem: --------- Modem PreDefined Info ------------------
I (9666) esp-modem: Model: ML302-DNLM/CNLM
I (9671) esp-modem: Modem itf: IN Addr:0x81, OUT Addr:0x01
I (9677) esp-modem: ----------------------------------------------------
I (9684) gpio: GPIO[12]| InputEn: 0| OutputEn: 1| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0
I (9694) gpio: GPIO[13]| InputEn: 0| OutputEn: 1| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0
W (9704) USB_HCDC: rx0 flush -0 = 0
W (9707) modem_board: DTE reconnect, reconnecting ...

W (10713) modem_board: reconnect after 5s...
W (11713) modem_board: reconnect after 4s...
W (12713) modem_board: reconnect after 3s...
W (13713) modem_board: reconnect after 2s...
W (14713) modem_board: reconnect after 1s...
I (14713) modem_board: Modem state STAGE_SYNC, Start
W (14824) modem_board: Network Auto reconnecting ...
I (14824) modem_board: Modem state STAGE_SYNC, Success!
I (14924) modem_board: Modem state STAGE_CHECK_SIM, Start
I (14958) modem_board: SIM Card Ready
I (14958) modem_board: Modem state STAGE_CHECK_SIM, Success!
I (15058) modem_board: Modem state STAGE_CHECK_SIGNAL, Start
I (15081) modem_board: Signal quality: rssi=25, ber=99
I (15081) modem_board: Modem state STAGE_CHECK_SIGNAL, Success!
I (15182) modem_board: Modem state STAGE_CHECK_REGIST, Start
I (15205) modem_board: Network registered, Operator: "46000"
I (15205) modem_board: Modem state STAGE_CHECK_REGIST, Success!
I (15306) modem_board: Modem state STAGE_START_PPP, Start
I (15715) modem_board: Modem state STAGE_START_PPP, Success!
W (15716) modem_board: Modem event! 0
I (15727) esp-netif_lwip-ppp: Connected
I (15727) esp-netif_lwip-ppp: Name Server1: 211.136.150.86
I (15727) esp-netif_lwip-ppp: Name Server2: 0.0.0.0
I (15732) modem_board: IP event! 6
I (15736) modem_board: Modem Connected to PPP Server
I (15742) modem_board: ppp ip: 10.84.162.74, mask: 255.255.255.255, gw: 192.168.0.1
I (15750) modem_board: Main DNS: 211.136.150.86
I (15755) modem_board: Backup DNS: 0.0.0.0
I (15761) pp: pp rom version: e7ae62f
I (15765) net80211: net80211 rom version: e7ae62f
I (15771) wifi:wifi driver task: 3fcb04d8, prio:23, stack:6656, core=0
I (15776) system_api: Base MAC address is not set
I (15781) system_api: read default base MAC address from EFUSE
I (15798) wifi:wifi firmware version: 133d2ca
I (15798) wifi:wifi certification version: v7.0
I (15799) wifi:config NVS flash: enabled
I (15800) wifi:config nano formatting: disabled
I (15804) wifi:Init data frame dynamic rx buffer num: 32
I (15809) wifi:Init management frame dynamic rx buffer num: 32
I (15815) wifi:Init management short buffer num: 32
I (15815) modem_board: Modem state STAGE_WAIT_IP, Start
I (15819) wifi:Init dynamic tx buffer num: 32
I (15825) modem_board: Modem state STAGE_WAIT_IP, Success!
I (15829) wifi:Init static tx FG buffer num: 2
I (15840) wifi:Init static rx buffer size: 1600
I (15844) wifi:Init static rx buffer num: 10
I (15848) wifi:Init dynamic rx buffer num: 32
I (15852) wifi_init: tcpip mbox: 32
I (15856) wifi_init: udp mbox: 6
I (15860) wifi_init: tcp mbox: 6
I (15864) wifi_init: tcp tx win: 5744
I (15868) wifi_init: tcp rx win: 5744
I (15873) wifi_init: tcp mss: 1440
I (15877) wifi_init: WiFi IRAM OP enabled
I (15881) wifi_init: WiFi RX IRAM OP enabled
I (15886) wifi_init: LWIP IRAM OP enabled
I (15892) phy_init: phy_version 503,13653eb,Jun  1 2022,17:47:08
I (15931) wifi:mode : softAP (7c:df:a1:e0:91:01)
I (15934) wifi:Total power save buffer number: 16
I (15934) wifi:Init max length of beacon: 752/752
I (15934) wifi:Init max length of beacon: 752/752
I (15939) modem_wifi: Wi-Fi AP started
I (15947) wifi:Total power save buffer number: 16
I (15948) modem_wifi: softap ssid: esp_4g_router password: 12345678
I (15954) modem_wifi: NAT is enabled

Debugging method

1. Debugging mode

Enable the 4G Modem Configuration -> Dump system task status option in menuconfig to print task detailed information.

Plaintext

```
I (79530) main: Task dump
I (79531) main: Load    Stack left      Name    PRI
I (79531) main: 3.24    1080    main    1
I (79532) main: 95.25   1248    IDLE    0
I (79536) main: 0.03    1508    bulk-out        6
I (79541) main: 0.03    1540    port    9
I (79546) main: 0.01    1752    Tmr Svc         1
I (79550) main: 0.04    2696    tiT     18
I (79554) main: 1.21    1352    usb_event       4
I (79559) main: 0.01    1532    bulk-in         5
I (79564) main: 0.05    3540    esp_timer       22
I (79569) main: 0.13    4632    wifi    23
I (79573) main: 0.00    1532    dflt    8
I (79577) main: 0.00    1092    sys_evt         20
I (79582) main: Free heap=37088 bigst=16384, internal=36968 bigst=16384
I (79589) main: ..............
```

2. Performance optimization

  1. If there is a requirement for throughput, please select the FDD standard module and operator;
  2. Modify APN to the name provided by the operator menuconfig -> 4G Modem Configuration -> Set Modem APN, for example, when using China Mobile's ordinary 4G card, it can be changed to cmnet;
  3. Configure ESP32-Sx CPU to 240MHz (Component config → ESP32S2-specific → CPU frequency), if it supports dual cores, please turn on both cores at the same time;
  4. Add and enable PSRAM (Component config → ESP32S2-specific → Support for external), and increase the PSRAM clock frequency (Component config → ESP32S2-specific → Support for external → SPI RAM config → Set RAM clock speed) select 80MHz. And open Try to allocate memories of WiFi and LWIP in SPIRAM firstly. in this directory;
  5. Increase the FreeRTOS Tick frequency Component config → FreeRTOS → Tick rate to 1000 Hz;
  6. Optimization of other application layers.

Performance test

Test environment:

  • ESP32-S2, CPU 240 MHz
  • 4 MB flash, no PSRAM
  • ML302-DNLM module
  • China Mobile 4G SIM card
  • Normal office environment

Test result:

Test item Peak Average
Download 6.4 Mbps 4 Mbps
Upload 5 Mbps 2 Mbps

4G Cat.1 theoretical peak download rate is 10 Mbps, peak upload rate is 5 Mbps The actual communication rate is affected by the operator's network, test software, Wi-Fi interference, and the number of terminal connections, etc.

Known Issues

  • ESP32-P4 currently does not support enabling the softAP function via esp_wifi_remote.

To create a project from this example, run:

idf.py create-project-from-example "espressif/iot_usbh_modem=1.1.2:usb_cdc_4g_module"

or download archive (~366.77 KB)