No port communication

I’m having a problem like that:

Modem Q2686RD DevStudio 3.1 Firmware 7.52.
When the application program is not loaded i can open the communication port in the Target Management perspective.
Once i have downloaded the application program the communication port does not work anymore.
If I try to open the door returns the following error:
'An error occurred During parsing of AT + WMSN response".

To make the communication port working again I have to delete the application with DwlWin.

It seems that the application does not leave time to communication.

Is your app using the serial port in “data” mode (e.g. through FCM service or through “Open Device” service)?
This would prevent DS to configure the port in Debug mode…

Or maybe your application is crashing early after module boot. In this case, the module would reset in loop some times before stabilizing and automatically stop the app…

I am using SPI communication between the modem and a microprocessor board. The communication program is controlled by a semaphore for the management of the data transmission/reception. Normally, the program waits on a semaphore that is released upon receipt of a message.

Mmm, maybe the issue is here.
AT commands are processed by the main Open AT app task, and DS needs to send AT commands to the module in order to get all features working.
If your app main task is blocked on a semaphore, I guess that AT commands are not working when your app is running, which would explain the behaviour you have.
My suggestion would be to deal with your SPI/semaphore handling in a secondary task, in order to let the main task always running.

Ok, now work fine,
tank you