Hello,

i am trying to setup my LPC1788 for using Multiple buffering, but so far I enable a second buffer, the screen shows nothing.

Here is my LCD_X_SHOWBUFFER case:

case LCD_X_SHOWBUFFER: {
LCD_X_SHOWBUFFER_INFO * p;
p = (LCD_X_SHOWBUFFER_INFO *)pData;
//
// Calculate address of the given buffer
//
BufferSize = (XSIZE * YSIZE * 16) / 8;
Addr = VRAM_ADDR_PHYS + BufferSize * p->Index;
//
// Make the given buffer visible
//

LPC_LCD->UPBASE = Addr;

//
// Send a confirmation that the buffer is visible now
//
GUI_MULTIBUF_Confirm(p->Index);
}
return 0;

I don´t understand, what I am doing wrong.
Can you please suggest how to do this.

Best regards,
marsal

Hello Adrian,

Thank you for your reply.
The "CopyBuffer" function is called after creating the display driver:

GUI_DEVICE_CreateAndLink(GUIDRV_LIN_16, COLOR_CONVERSION, 0, 0);
// Set custom callback function for copy operation
LCD_SetDevFunc(0, LCD_DEVFUNC_COPYBUFFER, (void (*)())_CopyBuffer);

Here is CopyBuffer function:

static void _CopyBuffer(int LayerIndex, int IndexSrc, int IndexDst) {
unsigned long BufferSize, AddrSrc, AddrDst;
// int i;
// int BITSPERPIXEL=LCD_GetBitsPerPixelEx(i);
//
// Calculate the size of one frame buffer
//
BufferSize = (XSIZE * YSIZE * 16) / 8;
//
// Calculate source- and destination address
//
AddrSrc = /*_VRamBaseAddr*/VRAM_ADDR_PHYS + BufferSize * IndexSrc;
AddrDst = /*_VRamBaseAddr*/VRAM_ADDR_PHYS + BufferSize * IndexDst;
memcpy((void *)AddrDst, (void *)AddrSrc, BufferSize);
}

I have checked all functions and it seems everything be right, but it works not.

Thank you,
marsal

Hello Adrian,

It works, if the Multiple Buffering turned off. I can not debug my programm, because I don't have a LPC-Link circuit board.

Best regards,
marsal

Hello Adrian,

I have tried to output a value from "VRAM_ADDR_PHYS" variable in the "_CopyBuffer" function:

//---------------------------------------------------------------------------------------
static void _CopyBuffer(int LayerIndex, int IndexSrc, int IndexDst) {
unsigned long BufferSize, AddrSrc, AddrDst;

BufferSize = (XSIZE * YSIZE * 16) / 8; // Calculate the size of one frame buffer

GUI_SetColor(0x7CFC00);
GUI_DispDecAt(VRAM_ADDR_PHYS,500,30, 10);

AddrSrc = /*_VRamBaseAddr*/VRAM_ADDR_PHYS + BufferSize * IndexSrc;
AddrDst = /*_VRamBaseAddr*/VRAM_ADDR_PHYS + BufferSize * IndexDst;

memcpy((void *)AddrDst, (void *)AddrSrc, BufferSize);
}
//---------------------------------------------------------------------------------------

On the screen appears only "-".

If I print out the Buffer variable, than it appears a right Value of "768000".
After this function is executed, the board hangs and does nothing from main function.

Therefore I assume, that "VRAM_ADDR_PHYS" is not defined.
How can I define the base video RAM address, that is allocated on my LPC1788 board?

Best regards,
marsal