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STM32F429I Discovery LCD Pin disconnected/malfunctioning

Question asked by qasim.hafiz on Feb 21, 2014
Latest reply on Mar 4, 2014 by qasim.hafiz
I have developed LCD driver for STM32F429I Discovery board using RGB565 (16bit) Pixel Format. My demo is displaying RED color filled rectangles by setting each RED pin (Total 5) one by one. i.e. 0x8000, 0x4000, 0x2000, 0x1000 and 0x0800 respectively.
Color displayed against 0x4000 is much closer to BLACK rather than RED. It appears either Second Last pin/bit (Second MSb) is either physically not connected or malfunctioning.

I have also tried ST Sample Code demo (LTDC ColorKeying) but behavior is same. After line number 87 of main.c file (Projects\Peripheral_Examples\LTDC_ColorKeying), Put following code to see behavior of LCD.

int x;
unsigned short Ymin, Ymax, Xmin, Xmax;

for (x = 0; x < 8; x++)
    Ymin = x*40;
    Ymax = Ymin + 40;
    Xmin = 0;
    Xmax = 239;
    Rectangle_Draw(Ymin, Ymax, Xmin, Xmax, (0x8000>>x)); // Function written below
// Function to Draw rectangle
void Rectangle_Draw(unsigned short Ymin, unsigned short Ymax, unsigned short Xmin, unsigned short Xmax, unsigned short col)
    unsigned short          *add = (unsigned short *) (LCD_FRAME_BUFFER);
    unsigned short          x, y;

    for(x=Xmin; x<Xmax; x++)
        for(y=Ymin; y<Ymax; y++)
            *(add + (y*240) + x) = col;