EC25 QuecOpen: Can MQTT, I2C ADC, GPIO control and USB networking run simultaneously?

Technical Subjects Open Solution
, ,
1

Hello Quectel Support,

I am developing a system based on the EC25 QuecOpen platform and would like to confirm whether the following architecture is officially supported and technically feasible.

My requirement is:

  • Run a custom application directly inside the EC25 QuecOpen Linux environment.
  • Keep an MQTT client connected to a remote MQTT broker.
  • Read an external ADC such as ADS1115 via I2C.
  • Use an EC25 GPIO to control the power enable pin of a Raspberry Pi Compute Module 4.
  • The EC25 should remain always powered.
  • When a command is received through MQTT, EC25 turns on the CM4 using GPIO.
  • After the CM4 boots, the EC25 should also provide mobile Internet access to the CM4 through USB.
  • EC25 should continue running its internal MQTT/I2C/GPIO application while the CM4 is simultaneously using the EC25 cellular connection through USB.

The expected architecture is:

LTE Network
    |
   EC25
    |
    +-- QuecOpen application
    |      +-- MQTT
    |      +-- I2C -> ADS1115
    |      +-- GPIO -> CM4 power enable
    |
    +-- USB -> Raspberry Pi CM4
              |
              +-- Internet through EC25

I have several questions:

  1. Can a QuecOpen application run continuously in parallel with the EC25 modem/network services?
  2. Can multiple threads or processes be used for MQTT, I2C and GPIO control?
  3. Is the EC25 I2C interface available to a QuecOpen Linux application, and is there an official example or API for accessing it?
  4. Which GPIO pins are recommended for controlling an external power-enable signal?
  5. Can the EC25 provide USB network access to a Linux host such as Raspberry Pi CM4 while the internal QuecOpen application is also using the cellular data connection?
  6. Which USB networking mode is recommended for this application: QMI, ECM, RNDIS or MBIM?
  7. Can both the EC25 internal Linux application and the USB-connected CM4 use the same PDP/data connection simultaneously?
  8. Does the QuecOpen firmware require any special USB composition or routing/NAT configuration for this?
  9. Are there any CPU, RAM, watchdog or stability limitations that should be considered when running this type of always-on application?

I would also appreciate any relevant QuecOpen SDK documents, GPIO/I2C examples, USB networking examples, or reference projects.

Thank you.

2
  1. Yes, it is supported.
  2. It is supported.
  3. Yes, you can find example code in folder ql-ol-extsdk/example/
  4. It depends on your hardware design.
  5. Yes, it is supported.
  6. It depends on your applicaiton. Quectel has no suggestions. ECM is suggested if both internal application and external devices need access internet via EC25
  7. Yes.
  8. Do not need.
  9. No limitations