graphics controller pmp drops out

Hello,

I designed a custom pcb which is nearly identical to the DA210 development board using the Truly tft display.  The only changes are some of the spi pins and touch control  pins are changed,  the graphics pins are the same.  I thought that getting the display running on the my custom board would be straight forward.  So far this has not been the case.

I have created a very basic program that uses the graphics display library to initialize the pmp, graphics, and output a basic color to the screen.  This program run fine on the development board, but creates a white screen not matter what I output on the custom board.  I have ensured that the proper driver is being used.  I have debugged the problem to the point of finding that the everything is initializing ok, but after settting the color and clearing the device, the color data is only sent to the display from the pmp once and it stops.  All the gclk, hsync, vsync, den signals keep running fine, but the gd15-0 data on the pmp stay high after the first frame is sent.

//basic code to test the display - blue should show up on display
ResetDevice();          // initialize the pmp and the graphics module
SetColor(BLUE);     //set the current color to blue
ClearDevice();          //clears the screen sets to current color

I found that running a loop fast enough works, but that the the colors quickly fade out from the display as they are not being updated.  

// this code displays colors being cycled, it appears to work, but enough time allows the display to fade out when not updated
while(1){
     for(i=0;i<0xffff;i++){

         SetColor(i);     //set the current color to blue
         ClearDevice();          //clears the screen sets to current color     
         DelayMs(10);

     }

}

I have checked the errata and could not find anything relative to this problem.  Support has been all but useless, as they post a quick guess to the problem and state the ticket is resolved.  Any ideas why the pmp, graphcs controller would not keep updating the pixel data??  Using compiler 3.24, library, 2.1 , device pic24fj256da210.  All connectors and hardware are identical to that being used on the DA development board.

Attached are the schematics of connections.  The board allows use of the edge connector which will mount the microchip truly board, or default connectors all for the display to be mounted directly to board.

Attachments:

Copy of Micro - TFT Controller R1.3.pdf