Display MI0283Qt9 conflicting with GSM-shield

hi,
I have an application with the GSM-shield (Quectel M10) using

  • voice calls,
  • SMS receive/send,
  • GSM client
    For the voice calls also a SD card is used.

Now I want to add a display MI0283Qt9 on a mSD-shield.

The GSM application works.
A test program with the display without GSM software also works.

But when I combine the GSM application with the display software then the plots on the display are ok but from the GSM application only the voice calls are still working.
The complete application is working without any error reports. The statements to receive and send an SMS are executed. But no SMS is sent.

When I switched to a GSM only software after having tried to send several SMSs with the complete application, all the old SMSs suddenly came out.

The GSM software is based on the GSM library and the display software is based on a library for this specific display.
The display interface is via SPI.

The hardware configuration is

  • Mega 2560
  • GSM shield with Quectel M10
  • mSD shield with SD card slot and connectors for the display
  • MI0283Qt9 display

The relevant part of the sketch within setup() is as following

// Start GSM shield
  // If your SIM has PIN, pass it as a parameter of begin() in quotes

  while (notConnected)
  { // GSM3ShieldV1AccessProvider::begin(..)
    if ( (gsmAccess.begin(PINNUMBER) == GSM_READY)  && 
         (gprs.attachGPRS(GPRS_APN, GPRS_LOGIN, GPRS_PASSWORD) == GPRS_READY) )
      notConnected = false;
    else
    {
      Serial.println("Not connected");
      delay(1000);
    }
  }
 
  spid.drawText(100,100,"GSM OK   ",FGColor,BGColor,1);  // this is a display function

  // This makes sure the modem correctly reports incoming events
  vcs.hangCall();
  client.stop();

  Serial.println("Waiting for a call or a SMS and wind data");

  // ***************** try to send a SMS, but it is not sent:
  Serial.println("SMS an mich");
  sms.beginSMS("016xxxxx473");
  sms.print("mal sehn, obs geht");
  sms.endSMS();
  Serial.println("\nCOMPLETE!\n");

Finally I started the complete application in debug mode (gsmAccess(true):wink: but I cannot interpret the output.
If somebody is interested in the output, here it is:

AT%13%
0 23>AT%13%%13%%10%OK%13%%10%%13%%10%Call Ready%13%%10%
AT+CGREG?%13%
23 54>AT+CGREG?%13%%13%%10%+CGREG: 0,2%13%%10%%13%%10%OK%13%%10%
AT+CGREG?%13%
54 85>AT+CGREG?%13%%13%%10%+CGREG: 0,1%13%%10%%13%%10%OK%13%%10%
AT+IFC=1,1%13%
85 102>AT+IFC=1,1%13%%13%%10%OK%13%%10%
AT+CMGF=1%13%
102 118>AT+CMGF=1%13%%13%%10%OK%13%%10%
AT+CLIP=1%13%
118 6>AT+CLIP=1%13%%13%%10%OK%13%%10%
ATE0%13%
6 17>ATE0%13%%13%%10%OK%13%%10%
AT+COLP=1%13%
17 23>%13%%10%OK%13%%10%
ATH%13%
23 29>%13%%10%OK%13%%10%
+++AT+QICLOSE%13% <-----is this ok?
53 53>
Waiting for a call or a SMS and wind data <----from Serial.print
SMS an mich <----from Serial.print
AT+CMGS=“016xxxxx473”%13% <----phone number changed for the forum
53 61>%248%%13%%10%RDY%13%%10%
mal sehn, obs geht%26%%13%
53 89>%248%%13%%10%RDY%13%%10%mal sehn, obs geht%13%%13%%10%ERROR%13%%10%

COMPLETE!

AT+CMGL=“REC UNREAD”,1%13%
89 4>AT+CMGL=“REC UNREAD”,1%13%%13%%10%+CME ERROR: 3517%13%%10%

At the end there are ERROR reports, e.g. +CME ERROR: 3517.

Can somebody explain to me what this error means?

I am really frustrated and hope to get good hints.

Thank you in advance.