EG91 Unstable USB Connection

IoT Modules LTE Standard Module
1

Hi,

I am experiencing some issues with the USB interface for the EG91. The goal is to interface it with an STM32H7, however the USB connection seems to be unstable. It also appears to be unstable when connecting the modem to my windows PC.

Could I please have the latest firmware for the EG91 (I am currently using EG91EXGAR08A05M1G). I understand there are some changes to the modems USB configuration in the firmware which may fix the issue, is that correct?

Thanks,

Andy

2

Could you tell me what kind of Driver do you use?

3

The windows driver is the Quectel LTE Windows USB Driver v2.0:

qcfilter.inf version:  08/22/2018,5.0.1.7
qcmdm.inf version:     08/22/2018,5.0.1.7
qcser.inf version:     08/22/2018,5.0.1.7
qcwwan.inf version:    08/22/2018,5.0.1.7

I am not aware of and driver for the STM32.

4

It is unstable when connecting the modem to your windows PC with this Quectel LTE Windows USB Driver v2.0, right?

5

That is correct yes, I can see the COM ports repeatedly connecting and disconnecting in the device manages. STM also reports that the modem repeatedly connects and disconnects too

6

sent you another Driver via email already, check please

7

I have received and installed the new drivers, thank you. There is still some disconnection events but much less than before. Are there any conditions (such as noise on the Vbus pin) that would cause the USB peripheral to reset but not the modem as a module?

8

Please could you send me the latest firmware for this modem so that I can use it for debugging the issue with an up to date image.

Thanks