recently I worked with the AT_passthrough on the SARA AFF R410M rev2 and everything worked fine.
The next day I wanted to continue but I did not get any response on the serial port anymore. There is no answer even on the “ATI9” command. Uploading the sketch again does not help.
When I upload another basic sketch like measuring battery voltage and temperature then everything works like expected including the serial port.
I am wondering if the SARA module got stuck in an undesired state when I removed the power supply. I read now in the SARA system integration manual that the supply should not be removed before the SARA module has been cleanly shut down by a AT+CPWROFF command.
I tried toggling the voltage pin on the R4xx as #monalisan suggested with no success.
Other error causes may be possible, too.
- What can I do to get it running again?
- What is your experience with “unclean” shut down, is that critical to avoid?
- Any tips on debugging problems with the SARA module on the board are appreciated.
Thanks for your help