Arduino Zero -> SmartGPU2 does not communicate

I am just beginning with the SmartGPU2 (4.3") display (using their SmartShield). I selected in the SmartGPU.h file the display size #define and compile test program BasicWindow. Compile failed- undefined Serial3.
I tried Serial2, same compile error. but with :

#ifdef ARDUINO_DUE //If arduino DUE is defined
#define SERIALPORT (Serial)

the compile is successful, but nothing happens on the SmartGPU2, and if I hook the USB cable to the laptop nothing displays on the monitor screen.

Has anyone figured out the serial connection? I think I am missing something simple.

Only Serial1 (pins 0 and 1) is configured on ZERO, see thread

Yes. I traced the SmartShield outputs to the SmartGPU2 and saw the serial comes from RX(0) and TX(1). A test program writing to Serial1 shows TX serial data on the TX(1) line, so now I can communicate with the SmartGPU2 device.

The next task is dealing with the SMARTGPU2.h library file. With the definition edited to read:

#define SERIALPORT (Serial1)

The sample programs compile but the scope on TX(1) shows no data.

By ignoring the SMARTGPU2 library and writing my own statements with Serial1.print() I have the board up and running. If I:

#include <SMARTGPU2.h>

With the library edited as per instruction for the serial port:
#define SERIALPORT (Serial1)

and the define for the display size 480x272

The example programs will compite but nothing but black is on the screen.

Debug statements using Serial.print send nothing to the monitor, though in my non-library test programs I can print to both the SmartGPU2 on Serial1 and the monitor on Serial, and using different baud rates for the two.

There must be some conflict between the SmartGPU2 library and the Serial library.

In the instantiation statement, before function setup():

SMARTGPU2 lcd;

This calls the function SMARTGPU2() found in SMARTGPU2.cpp library file:

//SmartGPU2 Library exclusive Functions - DO NOT MODIFY DOWN FROM HERE
//
/
/
/****************************************************************/
SMARTGPU2::SMARTGPU2(){
init();
}

The call to init() hangs up and setup() is never executed. The call to init() is not needed as in the setup() function the user will begin with another call to setup:

lcd.init();
lcd.start();

I have edited the offending line in SMARTGPU2.cpp to comment the call to init():

//SmartGPU2 Library exclusive Functions - DO NOT MODIFY DOWN FROM HERE
//
/
/
/****************************************************************/
SMARTGPU2::SMARTGPU2(){
//init();
}

The sample programs now run and the library is now useful. I am impressed with the screen.