USB connection between STM32F411 and modem RM500 quectel

[NRoma.6]

Hi I am working on a project where a need to send AT commands through my MCU to a modem, the problem is that this modem only has a USB interface and not a UART interface, so I have a lot of doubts of how should I do this, i wanted to use the USB_Host_Library but I dont know hot to send the data to a certain interface and enpoint, since que AT command interface appears as a virtual COM (Interface 2 with 3 endpoints).

And which class should I use? Communication Host class?

Thanks in advice, Nicolas.

[Sundar6444]

Hello Nicolas,

Were you able to figure out this? I am also trying to interface the STM32 with Quectel RM500Q and would like to know more about this topic. 

Thanks in advance

Sundar.

[Andrew Neil]

Similar recent question here:

https://community.st.com/t5/stm32-mcus-embedded-software/can-t-enumerate-telit-modem-usb-port-as-a-cdc-acm-device-with/m-p/704856#M50143

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@Sundar6444 wrote:

trying to interface the STM32 with Quectel RM500Q .

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Have you contacted Quectel for support with that?

Maybe they can suggest tips for interfacing this module to microcontrollers?

Maybe they can suggest a solution better suited for microcontroller connection?

[Sundar6444]

@Andrew Neil 

Thanks for sharing the link. It seems a lot of members are trying to interface STM controllers with modems.

Yes, i approached Quectel and looks like it is a dead end. They have asked me to develop a driver ourselves.