SSH connection over USB drops while testing legato app

1

I was testing a legato app which acquires GPS coordinates on WP7702, the app is programmed to constantly send GPS in SMS to my cell phone for 4 mins, but my cell phone only received the SMS for approx 1-2 mins, and I looked at the terminal trying to figure out what was going wrong on Legato app, I found out the the ssh connection drops:

packet_write_wait: Connection to 192.168.2.2 port 22: Broken pipe

Screen Shot 2021-08-05 at 3.00.07 PM
Screen Shot 2021-08-05 at 3.00.07 PM2312×264 67.9 KB

Then I had to wait a few second to ssh reconnect to the target over USB. I connected wp7702 to a macbook BTW.

Can anyone help me figure out the issue is from target or legato app?

2

Do you see problem in ubuntu linux machine?

3

I don’t really have an ubuntu machine, I could only install a virtual ubuntu machine to see if it would happen. Will that be okay? any particular ubuntu version it requires?

Also, I forgot to mention, the app seems to stop working while ssh connection drops.

4

is it a module reset case?

5

I don’t think so. does the system log the reset?
As far as I can tell, the legato app has a SQLite database, if a reset occurred, the database would also be reset, I just checked the database, it looks good as before. so I dont think that was a reset…

6

do you have the UART console?
It will show there.

7

No, do I have to install it on my computer?

8

you can check the schematic, there should be a USB port for UART2

9

I found it, I actually use that port for SSH connection. How could I use it for UART2 though?

10

Ssh is using usb port, uart2 is just a serial port

11

Are we talking about MangOH red WP7702? I can’t find any serial port either on device or user guide manual

12

There are two usb ports on the mangoh red board, one is connected to usn of module, one is connected to uart2 of module

13

I think I found it, how could I get UART console on my computer then?

14

I think so , if you have set AT!MAPAURT=16,2 which to choose console function for UART2

15

when I set AT!MAPUART=16,2 how could I see UART console then? would ssh connection still be working?

16

Did you see a com port in device manager?
You can use tera term to open the port

17

I have set it, but cant find the port you mentioned:
AT!MAPUART
image
Device Manager
image

18

Did you connect the CN800 to PC?

https://www.manualslib.com/manual/1843614/Mangoh-Yellow.html?selected=1&page=31#manual

19

yes I did, mangoh red has only two usb ports and I have had both connected to PC

20

Then it should have a com port in device manager …