TFT_WHITE is less than full brightness

[daxliniere]

I had been thinking my screen looked a bit dull, when I realised that, on reset, the white background is actually brighter than when the screen is filled with TFT_WHITE (0xFFFF).

Is there any way to overcome this? The LCD I'm using is 3.5" ILI9488.

All the best,
Dax.

[Bodmer]

This maybe due to the Gamma values not being optimised for your particular display. Try to get the initialisation settings from the manufacturer and compare to the init sequence here:
https://github.com/Bodmer/TFT_eSPI/blob/master/TFT_Drivers/ILI9488_Init.h

[daxliniere]

Cool, thanks. I'll see if I can find and then report back in case you want to update it in your library.

[daxliniere]

Would it be possible for me to work this out with trial and error if I can't get details from MFG?

[daxliniere]

How's this?

void LCD_Init(void)
{
	unsigned char i;

    SPI_CS=0;
	//Sleep in

SPI_WriteComm(0xE0); //P-Gamma
SPI_WriteData(0x00);
SPI_WriteData(0x08);
SPI_WriteData(0x0C);
SPI_WriteData(0x02);
SPI_WriteData(0x0e);
SPI_WriteData(0x04);
SPI_WriteData(0x30);
SPI_WriteData(0x45);
SPI_WriteData(0x47);
SPI_WriteData(0x04);
SPI_WriteData(0x0c);
SPI_WriteData(0x0a);
SPI_WriteData(0x2e);
SPI_WriteData(0x34);
SPI_WriteData(0x0F);

SPI_WriteComm(0XE1); //N-Gamma
SPI_WriteData(0x00);
SPI_WriteData(0x11);
SPI_WriteData(0x0d);
SPI_WriteData(0x01);
SPI_WriteData(0x0F);
SPI_WriteData(0x05);
SPI_WriteData(0x39);
SPI_WriteData(0x36);
SPI_WriteData(0x51);
SPI_WriteData(0x06);
SPI_WriteData(0x0f);
SPI_WriteData(0x0d);
SPI_WriteData(0x33);
SPI_WriteData(0x37);
SPI_WriteData(0x0F);

SPI_WriteComm(0XC0); //Power Control 1
SPI_WriteData(0x17); //Vreg1out
SPI_WriteData(0x15); //Verg2out

SPI_WriteComm(0xC1); //Power Control 2
SPI_WriteData(0x41); //VGH,VGL

SPI_WriteComm(0xC5); //Power Control 3
SPI_WriteData(0x00);
SPI_WriteData(0x48); //Vcom
SPI_WriteData(0x80);

SPI_WriteComm(0x36); //Memory Access
SPI_WriteData(0x08);

SPI_WriteComm(0x3A); // Interface Pixel Format
SPI_WriteData(0x66);

SPI_WriteComm(0XB0); // Interface Mode Control
SPI_WriteData(0x00);
SPI_WriteComm(0xB1); //Frame rate
SPI_WriteData(0xA0); //60Hz
SPI_WriteComm(0xB4); //Display Inversion Control
SPI_WriteData(0x02); //2-dot

SPI_WriteComm(0XB6); //RGB/MCU Interface Control
SPI_WriteData(0x20); //MCU

SPI_WriteData(0x22); //Source,Gate scan dieection

SPI_WriteComm(0XE9); // Set Image Function
SPI_WriteData(0x00); // Disable 24 bit data input
SPI_WriteComm(0xF7);
//Adjust Control
SPI_WriteData(0xA9);
SPI_WriteData(0x51);
SPI_WriteData(0x2C);
SPI_WriteData(0x82);
//D7 stream, loose
SPI_WriteComm(0x21); //Sleep out
SPI_WriteComm(0x11); //Sleep out
Delay(120);
SPI_WriteComm(0x29);
}

[daxliniere]

Also, can you do damage to a screen/chip by using an incorrect initialisation?

[Bodmer]

I am not aware of any situations where settings cause damage. It would be a poor design if that did happen as the display might easily receive random data in some situations like power up where output pins are not yet defined.