EM7430 send AT command no response

Hello,

My EM7430 LTE module has some troubles.
I modified qcserial.c and qmi_wwam.c in kernel driver,
and embedded board got 3 ttyUSB & “cdc-wam” interfaces.
Below is information:

I tried to send AT command to ttyUSB0-2, but they had not any responses.
for example:

Please help me to solve it, or give me some information.
Thank you very much.

Best Regards,
Allen

Allen,

Please do not use the QC default drivers supplied with the kernel we have seen horrendous problems with them. You need to use our GobiSerial and GobiNet drivers on the source at the link below.

http://source.sierrawireless.com/~/media/support_downloads/airprime/software/sierralinuxqmidriverss2.25n2.36.tar.ashx

After you build them into the system make sure it is actually using them, Linux really likes the QC drivers and you may have to manually delete the .ko files to force it to use the Gobi files.

Regards

Matt

Hi mlw,

Thank you for your reply.
Actually I also porting the GobiSerial driver without GobiNet, and EM7430 had the same situation.
Totay I porting GobiSerial and GobiNet again, but GobiNet has error.

And AT command still no any responses.

Could you give me more information?
Thank you very much.

Best Regards,
Allen

Allen,

So you are using minicom to connect to /dev/ttyUSB2 and there is no response from it?

Regards

Matt

Hi Matt,

I only use “cat” command to monitor /dev/ttyUSB2.
Because I use AC341U USB dongle, and it has receive responses.
So I need to use minicom replace “cat” command?
If yes, I will build minicom to test it.

Thank you very much.

Best Regards,
Allen

Allen,

I would suggest using minicom as it is the most reliable tool to work with the AT commands and will mean you are using a known good method.

Regards

Matt

This is nnews to me. Could you please provide enough details to get whatever problem you see fixed?

I have seen this symptom on the MC7455 and EM7455 a few times without yet being able to pinpoint the actual problem. What I have found is that a “usb device reset” (not a modem reset - that does not help) “fixes” the problem. At least it has for me. No guarantees, but worth trying.

The easiest way to do a usb reset on linux is by using the “usbreset” utility, which is now part of the usbutils collection. Get it from your favourite distro, or see here: github.com/gregkh/usbutils/blob … usbreset.c

We have not ‘fixed’ anything we have just written our own new drivers, I know some engineers internally who ae pretty scathing about the QC open source drivers particularily the qmi_wwan ones.

Regards

Matt

I am sure you are right. But I still wish they would share those problems so that the problems could be fixed. Using GobNet and GobiSerial is definitely correct for anyone who wants to develop a Sierra supported solution. Or for anyone having problems with the qcserial/qmi_wwan drivers. Or simply to eliminate drivers as a source of any observed problem.

But even if one set of working drivers is enough, it would still be nice to have any known issues with the qcserial/qmi_wwan drivers fixed as well. Don’t you think so?

Frankly, I do not see why you cannot qualify these problems if you “know” about them. There never is much point in referring to problems you are unable to describe. It just looks like FUD. At least to me. Sorry.

We don’t ‘know’ about them, we have seen them and pushed customers to use software we know works and we are able to support. It is not our place to support open source software, particularly software that is used in direct competition to the hardware that we sell.

As I am sure you know, every system is different and as such something that affect one system will have no effect on another (I ran with qcserial for a couple of years without realising it until I plugged a unit with a specific combination of firmware in and it all went wrong).

I am sorry if you do not like this approach but we do have a business to run.

Regards

Matt

Fully understood, and agreed.

But I take any reports of problems seriously. If you have a problem and want it fixed, then please give details. If you have a problem and don’t want it fixed, tben please don’t tell me that you have a problem in the first place :wink:

This makes me very sorry to hear.

And I sincerely believe you are wrong. The Sierre Wireless QMI SDK is a unique product which in no way can be replaced by any community developed and unsupported software. There just is no competition there. On the contrary: Those “products” complete each other by making Sierra Wireless modems available to a larger set of end users.

Yes, I know. Which is why I wanted to know more details. We can only improve if we know about the specific cases where it goes wrong.

GobiSerial is open source too. Of course you do not need to support qcserial, but if you happen to find problems, then you can report them and they will be fixed. This is not “supporting”.

Also you hopefully have an endeavour that the devices you sell are working correctly. And since qcserial is in the kernel (as opposed to GobiSerial) you have a direct advantage if the devices are working with this driver. The modems you sell are in various Laptops and dongles, people who are using them are most likely not to use GobiNet and GobiSerial for their standard usecase of “Internet access”.

For OP: I am using screen for accessing the serial ports. You need to make sure that only one program is accessing the serial port at the same time.

Hi Matt,

I use minicom to connect EM7430, and it still no response.
What is step I lose?
Thank you.

Best Regards,
Allen

Allen,

Can you send the following to a terminal with the unit plugged in

uname -r
lsusb
ls /dev
lsmod

Regards

Matt

Hi Matt,

FYI

Thanks you.

Best Regards,
Allen

Allen,

Ok so you are using Open WRT and not pure Linux then? The drivers are intended specifically for Linux and while they are close as OS’s they aren’t exactly the same, I do not know why you are unable to send the AT commands. I know there are people who have got it working but I do not know how.

Regards

Matt

Hi Matt,

Thanks for your help.
I have some questions about:
1.If EM7430 is not have firmware, it might probe successfully?
Because I am not sure that EM7430 has firmware or not.
2.I found electronic SPEC in datasheet, and hardware issue might cause ttyUSB abnormally?

Attachment is GobiNet debug log.

Thank you very much.

Best Regards,
Allen
GobiNet fail.txt (15.9 KB)

You could also try typing aten then enter, then ati into minicom (or screen)

Although I think that qcserial is not the problem: You could try using GobiSerial for the serial ports.

Hi fs1,

Thanks for your reply.
I try your recommendation, but it still no any responses.
Maybe it has hardware issue with my board, I will debug it.
Thank you.

Best Regards,
Allen