PIC : Problem with LCD Initialization

Question

As we are developing our application based on the PIC18F66K22. We need to interface LCD with it. We have the LCD working with it but the problem that we are getting is that the LCD initialization takes around 10 Sec and only after that the LCD starts till then even microcontrooller does not execute any commands.But after initialization it works as expected without any delay. What might be causing the problem ? The LCD controller is ili9163C. The datasheet can be found at https://www.displaytech-us.com/sites/default/files/driver-ic-data-sheet/ILI9163C_DS_V010_2011_0118.pdf .

The following is the initialization code.

void LCD_init()
{
Send_Command(0x11); //Exit Sleep   
delay_ms(50);   
Send_Command(0x26); //Set Default Gamma   
Send_Data(0x04);   
// Send_Command(0xF2); //E0h & E1h Enable/Disable   
// Send_Data(0x00);   
Send_Command(0xB1);   
Send_Data(0x0C);   
Send_Data(0x14);   
Send_Command(0xC0); //Set VRH1[4:0] & VC[2:0] for VCI1 & GVDD   
Send_Data(0x0C);   
Send_Data(0x05);   
Send_Command(0xC1); //Set BT[2:0] for AVDD & VCL & VGH & VGL   
Send_Data(0x02);   
Send_Command(0xC5); //Set VMH[6:0] & VML[6:0] for VOMH & VCOML   
Send_Data(0x29);   
Send_Data(0x43);   
Send_Command(0xC7);   
Send_Data(0x40);   
Send_Command(0x3a); //Set Color Format   
Send_Data(0x55);   
Send_Command(0x2A); //Set Column Address   
Send_Data(0x00);   
Send_Data(0x00);   
Send_Data(0x00);   
Send_Data(0x7F);   
Send_Command(0x2B); //Set Page Address   
Send_Data(0x00);   
Send_Data(0x00);   
Send_Data(0x00);   
Send_Data(0x9F);   
Send_Command(0x36); //Set Scanning Direction   
Send_Data(0xA8);   
Send_Command(0xB7); //Set Source Output Direction   
Send_Data(0x00);   
Send_Command(0xf2); //Enable Gamma bit   
Send_Data(0x01);   
Send_Command(0xE0);   
Send_Data(0x36);//p1   
Send_Data(0x29);//p2   
Send_Data(0x12);//p3   
Send_Data(0x22);//p4   
Send_Data(0x1C);//p5   
Send_Data(0x15);//p6   
Send_Data(0x42);//p7   
Send_Data(0xB7);//p8   
Send_Data(0x2F);//p9   
Send_Data(0x13);//p10   
Send_Data(0x12);//p11   
Send_Data(0x0A);//p12   
Send_Data(0x11);//p13   
Send_Data(0x0B);//p14   
Send_Data(0x06);//p15   
Send_Command(0xE1);   
Send_Data(0x09);//p1   
Send_Data(0x16);//p2   
Send_Data(0x2D);//p3   
Send_Data(0x0D);//p4   
Send_Data(0x13);//p5   
Send_Data(0x15);//p6   
Send_Data(0x40);//p7   
Send_Data(0x48);//p8   
Send_Data(0x53);//p9   
Send_Data(0x0C);//p10   
Send_Data(0x1D);//p11   
Send_Data(0x25);//p12   
Send_Data(0x2E);//p13   
Send_Data(0x34);//p14   
Send_Data(0x39);//p15   
Send_Command(0x29); // Display On
}

This is the main section

void main()
{
OSCCONbits.IRCF0 = 1;   //HFINTOSC 16MHz with PLLEN
OSCCONbits.IRCF1 = 1;
OSCCONbits.IRCF2 = 1;
OSCTUNEbits.PLLEN = 1;
delay_ms(5);
while(!OSCCONbits.IRCF2);   //wait for HF-INTOSC oscillator frequency is stable
delay_ms(5);
    Config_IO();
    lcd_reset();    //LCD reset
delay_ms(5);    //LCD reset complete delay`
    LCD_init();
font_init();

    TRISBbits.TRISB3 = 0;
TRISCbits.TRISC2 = 0;
RELAY_EN = 0;

FillFullLcd(WHITE);
//LCD_image (0,33,159,96,(unsigned char rom *)benchmark);
// sprintf(&FirmVerText[6],"%d.%d",FW[0]-0x30,FW[1]-0x30);
// setfont((void *)font_Calibri_10);
// LCD_OutText(50,97,FirmVerText,BLACK);
setfont((void *)font_Calibri_10); //added by shailesh
    LCD_OutText(50,99,FirmVerText,BLACK);//added by shailesh
    LCD_image (0,33,159,96,(unsigned char rom *)benchmark);
    delay_ms(3000);
    FillFullLcd(BLUE);
    Hstart = 0;
    Vstart = 0;
    radius = 5;
    Hend = 100;
    Vend = 75;
    color = BLUE;
LCD_draw_round_corner_box(2,33,157,96,75,LOGOC,1);
//LCD_Rectangle(2,33,157,96,LOGOC,1);
LCD_OutText(35,55, productstr,WHITE);
    delay_ms(2000);
    calibration();
    while(1);
    }

Here in this code it takes around 10 sec to paint the entire screen blue. but after that all the lcd operations are working perfectly fine and without delay. What might be causing the problem here ?

Answer 1

It is really hard to tell from your posted code, much of which is missing, what could be consuming all the time.

You'll need to do some work to narrow down just where all the delays are. A tried and true way to do this is to find an I/O pin that is currently idle or not used and set it up as an output DEBUG pin. Then start setting this pin high and then back low at various points in your code wake up and initialization flows. Putting this signal on an oscilloscope along with the MCU Reset signal will let you characterize how long various parts of the code are taking to run.

Within a short time you will be able to determine if it is the MCU oscillator startup code, the length of time it takes to run the LCD init routine or how long it takes to run the FillFullLcd() routine. <- These are just examples. It could be something else.

Answer 2

delays should be defined 2-5ms froom enable to preamble and 20-50 for latch after initialization command then a larger one after initialization for control commands always sustaining enable pin delays for each case depending the interfacing ex. hc164... enable to low should maybe also be preceded by a short delay to ensure display controller has latched.

Answer 3

Actually we have solved this problem. The problem was caused by the 50 ms delay after "wake up from the sleep" command. After removing the delay the LCD is now working perfectly fine. I guess the 50 ms delay is causing the LCD controller to wake up from the sleep.