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the problem of STM32F439 about the LCD_FRAME_BUFFER

Question asked by roy on May 3, 2013
Latest reply on May 3, 2013 by jj.sprague
hello, i have a eval board of STM32F439.i have some problems.
the first one:
when i used the  LCD-TFT Controller to display the LCD,I found the demo have a code of
 #define LCD_FRAME_BUFFER   ((uint32_t)0xC0000000)
#define BUFFER_OFFSET          ((uint32_t)0x130000)
i don't know why ,where i can found ,it should be the address,right?but i don't know how to get it?
In the data sheet is LTDC Layerx Color Frame Buffer Address Register (LTDC_LxCFBAR),This register defines the color frame buffer start address which has to point to the address, where the pixel data of the top left pixel of a layer is stored in the frame buffer.
why the address 0xc000000 ,not the others,i change the address,i found it can't display。the BUFFER_OFFSET  ((uint32_t)0x130000),why ?
the second :
/* Internal Buffer defined in SDRAM memory */
uint32_t uwInternelBuffer = 0xC0260000;
that why? i don't know why the SDRAM address is 0xC0260000,i change it,but have some problems.SDRAM.png

i can't understand.can you help me ? Thank you very much?
the board is the eval .the mcu is STM32F439.