ILI9341 via 6-bit RGB mode...

ASergej · October 28, 2015

Hi!

I'm trying to start using uGFX with ILI9341 (MIO283QT-13) via 6-bit RGB-mode. And I have some problems with the display driver.

I setup the display using SPI:


// HW reset
	Reset_HW_LCD();

// SW reset
	Write_CMD_LCD(0x01);
	DummyWait(30000);	// ~1 ms

// display OFF
	Write_CMD_LCD(0x28);

// Power Control B
	Write_CMD_LCD(0xCF);
	Write_DATA_LCD(0x00);
	Write_DATA_LCD(0x81);
	Write_DATA_LCD(0x30);

// Power ON sequence control
	Write_CMD_LCD(0xED);
	Write_DATA_LCD(0x64);
	Write_DATA_LCD(0x03);
	Write_DATA_LCD(0x12);
	Write_DATA_LCD(0x81);

// Driver Timing Control A
	Write_CMD_LCD(0xE8);
	Write_DATA_LCD(0x85);
	Write_DATA_LCD(0x01);
	Write_DATA_LCD(0x79);

// Power Control A
	Write_CMD_LCD(0xCB);
	Write_DATA_LCD(0x39);
	Write_DATA_LCD(0x2C);
	Write_DATA_LCD(0x00);
	Write_DATA_LCD(0x34);
	Write_DATA_LCD(0x02);

// Pump ratio control
	Write_CMD_LCD(0xF7);
	Write_DATA_LCD(0x20);

// Driver Timing Control B
	Write_CMD_LCD(0xEA);
	Write_DATA_LCD(0x00);
	Write_DATA_LCD(0x00);

// Power control 1
	Write_CMD_LCD(0xC0);
	Write_DATA_LCD(0x26);

// Power control 2
	Write_CMD_LCD(0xC1);
	Write_DATA_LCD(0x11);

// VCOM control 1
	Write_CMD_LCD(0xC5);
	Write_DATA_LCD(0x35);
	Write_DATA_LCD(0x3E);

// VCOM control 2
	Write_CMD_LCD(0xC7);
	Write_DATA_LCD(0xBE);

// Memory access control
	Write_CMD_LCD(0x36);
	Write_DATA_LCD(0x48);

// Pixel format set
	Write_CMD_LCD(0x3A);
	Write_DATA_LCD(0x66); // 18 bit for pixel

// Frame rate control
	Write_CMD_LCD(0xB1);
	Write_DATA_LCD(0x00);
	Write_DATA_LCD(0x1B);

// Enable 3Gamma
	Write_CMD_LCD(0xF2);
	Write_DATA_LCD(0x02);

// Gamma set
	Write_CMD_LCD(0x26);
	Write_DATA_LCD(0x01);

// Positive Gamma correction
	Write_CMD_LCD(0xE0);
	Write_DATA_LCD(0x1F);
	Write_DATA_LCD(0x1A);
	Write_DATA_LCD(0x18);
	Write_DATA_LCD(0x0A);
	Write_DATA_LCD(0x0F);
	Write_DATA_LCD(0x06);
	Write_DATA_LCD(0x45);
	Write_DATA_LCD(0x87);
	Write_DATA_LCD(0x32);
	Write_DATA_LCD(0x0A);
	Write_DATA_LCD(0x07);
	Write_DATA_LCD(0x02);
	Write_DATA_LCD(0x1F);
	Write_DATA_LCD(0x07);
	Write_DATA_LCD(0x05);
	Write_DATA_LCD(0x00);

// Negative Gamma correction
	Write_CMD_LCD(0xE1);
	Write_DATA_LCD(0x00);
	Write_DATA_LCD(0x25);
	Write_DATA_LCD(0x27);
	Write_DATA_LCD(0x05);
	Write_DATA_LCD(0x10);
	Write_DATA_LCD(0x09);
	Write_DATA_LCD(0x3A);
	Write_DATA_LCD(0x78);
	Write_DATA_LCD(0x4D);
	Write_DATA_LCD(0x05);
	Write_DATA_LCD(0x18);
	Write_DATA_LCD(0x0D);
	Write_DATA_LCD(0x38);
	Write_DATA_LCD(0x3A);
	Write_DATA_LCD(0x1F);

// Column set
	Write_CMD_LCD(0x2A);
	Write_DATA_LCD(0x00);
	Write_DATA_LCD(0x00);
	Write_DATA_LCD(0x00);
	Write_DATA_LCD(0xEF);

// Page set
	Write_CMD_LCD(0x2B);
	Write_DATA_LCD(0x00);
	Write_DATA_LCD(0x00);
	Write_DATA_LCD(0x01);
	Write_DATA_LCD(0x3F);

// Entry mode set
	Write_CMD_LCD(0xB7);
	Write_DATA_LCD(0x07);

// RGB...
	Write_CMD_LCD(0xB5);
	Write_DATA_LCD(0x04);
	Write_DATA_LCD(0x02);
	Write_DATA_LCD(0x0A);
	Write_DATA_LCD(0x14);

	Write_CMD_LCD(0xB0);
	Write_DATA_LCD(0x60);

	Write_CMD_LCD(0xB1);
	Write_DATA_LCD(0x00);
	Write_DATA_LCD(0x1F);

	Write_CMD_LCD(0xF6);
	Write_DATA_LCD(0x00);
	Write_DATA_LCD(0x00);
	Write_DATA_LCD(0x07);

// Display function control
	Write_CMD_LCD(0xB6);
	Write_DATA_LCD(0x00);
	Write_DATA_LCD(0x80);
	Write_DATA_LCD(0x27);
	Write_DATA_LCD(0x00);

// Sleep OUT
	Write_CMD_LCD(0x11);
	DummyWait(3000000);	// ~100 ms

// Display ON
	Write_CMD_LCD(0x29);
	DummyWait(3000000);	// ~100 ms

	Write_CMD_LCD(0x2C);

After that, I start transfer data via parallel interface. I send: 1) all data "0xFF" or 2) all data "0x00".

DOTCLK = 8 MHz, 6-bit parallel (3 transfer/pixel), Thsync = 10 dotclk width, Thsync = 760 dotclk period and Tvsync = 2*760 dotclk width and Tvsync = 324*760 dotclk period

But in both cases I see only white-gray lines on the display.

What am I doing wrong?

Edited October 29, 2015 by Guest

Joel Bodenmann · October 29, 2015

Hello ASergej and welcome to the community!

Right now I don't have the time to look at the datasheet and I don't know the proper initialization codes for the 6-Bit mode out of my head.

Is this a custom board or is this a dev-board that you bought? If it is a dev-board I would highly recommend you grabbing the initialization code from the example(s) that came with the board and putting those into the init() call of the GDISP driver.

Did you also check with a logic analyzer whether the data is sent properly?

Another thing that usually helps is to lower the clock frequency to something below 1 MHz in order to minimize the odds of hardware issues.

I will take a look at the datasheet and your initialization code tonight.

~ Tectu

ASergej · October 29, 2015

Thank you very much for your answere.

This is my custom board with BF-527. But despite this, I've never seen init-code for ILI93xx in 6/8 RGB mode for any dev-board (wich mcu - it does not matter) .

Yes, I check all signals and all of them look good. And rising/falling edges - is ok. 8 MHz - it's not this problem.

Furthermore, I transmit data to display in:

1) SPI-mode (via SPI) - it's all ok;

2) 18-bit RGB-mode, but I used only lower 6-bit of data (D0-D5) and I saw only blue or black color on the screen. Another 12 bit of data - I tied them to ground. It means - it's all ok in this mode.

I think, I'm wrong in some signal's parameters in this 6-bit RGB mode... period or width Thsync, Tvsync... or, may be, some settings of ILI9341...

But I have no idea where I could be wrong.

Thank you for your help!

Joel Bodenmann · October 29, 2015

It's already very good to know that you got it working in the two other modes. This way we know that it is an initialization issue for sure.

I'll take a look at the datasheet tonight and compare it to your initialization code. Sorry for the delay.

~ Tectu

ASergej · October 29, 2015

It's all ok.

I will be waiting for your comments...

Thank you!

Joel Bodenmann · October 30, 2015

I assume that you understand that there are two different interfaces: The MCU interface and the RGB interface. The RGB interface allows you to directly stream pixel information from a frame buffer (eg. the LTDC of an STM32). However, you still need the MCU interface to first configure the display controller. Page 45 in the datasheet mentions that you have to use the SPI interface for that - are you doing that?

I didn't find anything in your initialization code that seems to be wrong. Even the timings are spot-on.

Can you give a few more information about the microcontroller side of your hardware? Are you sure that the microcontroller that you are using is capable of driving an RGB panel in 3x 6-bit mode? Did you verify that the timings are set up correctly in the microcontroller too?

Can you verify that the microcontroller is properly generating the VSYNC, HSYNC and DOTCLK signals? There is a timing diagram for the 18-bit RGB interface in the datasheet on page 49. I would recommend you to grab your logic analyzer / oscilloscope and having a look.

~ Tectu

ASergej · October 30, 2015

Of course, you're right. I don't use MCU (i-8080) interface.

I setup the display using SPI interface (I wrote to you about this befor), and after that I start to transmit data continuously via parallel RGB-interface.

I use ADSP-BF527 DSP. This is very fast DSP and it have PPI-interface for connecting to RGB-interface. But It does not matter.

Because, I wrote to you, that in full 18-bit RGB mode - all is working properly, but LCD don't work in 3x6-bit RGB mode (3 transfer for 1 pixel RGB mode).

All is working in 18-bit RGB mode - it means, I generate all signal properly: all what I write in the source code - I have physically.

I wrote to you:

"I think, I'm wrong in some signal's parameters in this 6-bit RGB mode... period or width Thsync, Tvsync... or, may be, some settings of ILI9341..."

For 3x6 bit RGB mode

The command 0xB5 sets: VFP = 0x4,VBP=0x2,HFP=0xA,HBP=0x14 (page 46)

Tlow HSYNC = 10 DOTCLK, Tlow VSYNC = 2 lines

HSYNC: Tlow = 10 DOTCLK, Tperiod = Tlow + HBP + 240 pixels*3 transfer + HFP = 10 + 20 + 240*3 + 10 = 760 DOTCLK

VSYNC: Tlow = 2 lines, Tperiod = Tlow + VBP + 320 lines + VFP = 2 + 2 + 320 + 4 = 328 lines => Tperiod = 328*760 DOTCLK

And I have 3 displays MIO283. All of them working alike.

What do you think about PCDIV? (0xB6 command and page 47)

What value do I need to set for PCDIV, DIV and RTN?

P.S.: for 18-bit RGB mode.

HSYNC: Tperiod = 280 DOTCLK, Tlow = 10 DOTCLK

VSYNC: Tperiod = 328*280 DOTCLK, Tlow = 2*280 DOTCLK

Freq DOTCLK = 6,35 MHz.

In this mode all working properly!

Joel Bodenmann · November 2, 2015

Hello Sergej,

We will have a look at your timings this Wednesday afternoon. Sorry for the delay - we are currently very busy.

~ Tectu

ASergej · November 3, 2015

Ok!

I will be waiting for your comments...

Thank you!

ASergej · November 3, 2015

I solved this problem! Damn...

I will write about it tomorrow...

Joel Bodenmann · November 4, 2015

Glad to hear that you got it working. We're interested into hearing what the issue was.

Sorry that we couldn't help any sooner. We are currently very busy adding support for new platforms and preparing a new release for both the studio and the actual library itself.

~ Tectu

ASergej · June 6, 2017

Be careful with HSYNC and VSYNC timing... All problems from their incorrect difinition.

For 6-bit RGB and 18 bit/pixel format:

// timers for HSYNC and VSYNC...
   *pTIMER_DISABLE = 0xFF;   // all timers - stop...
   *pTIMER_STATUS = 0xFFFF; // all flags - clear...

   *pTIMER0_CONFIG = 0x02B9;
   *pTIMER1_CONFIG = 0x02B9;

// for HSYNC (clk)
*pTIMER0_WIDTH = 10;

*pTIMER0_PERIOD = 760; // CLK = (240+13)*3 + 1 = 760 - this is row

// for VSYNC (clk)
*pTIMER1_WIDTH = 2*760;

*pTIMER1_PERIOD = 324*760;

// CLK - 10 MHz
   *pTIMER5_CONFIG = 0x0219;

   *pTIMER5_WIDTH = 3;

   *pTIMER5_PERIOD = 7;

   asm("ssync;");

// blackfin DMA PPI...

*pDMA0_CONFIG = 0; // DMA0 - clear

*pDMA0_PERIPHERAL_MAP = 0x0000; // set DMA0 for PPI

   *pDMA0_START_ADDR = &DisplayMEM[0]; // set screen array...

   *pDMA0_X_COUNT = 760;
   *pDMA0_X_MODIFY = 1;

   *pDMA0_Y_COUNT = 324;
   *pDMA0_Y_MODIFY = 1;

   *pDMA0_CONFIG = 0x1091; // DMA enable...

   asm("ssync;");

// blackfin PPI...
*pPPI_STATUS = 0;
*pPPI_DELAY = 0;

   *pPPI_COUNT = 759; // 760 active byte

   *pPPI_CONTROL = 0xC01F;   // PPI enable...
   *pTIMER_ENABLE = 0x3|(1<<5); // running...
     asm("ssync;");

We have DisplayMEM - screen array, but it has some "blind" areas.

All working code (with descriptor model for BF-527).

In this code, screen array - has NO "blind" areas.

Array is copy of visible screen.

Init_SPI_LCD();

// HW reset
Reset_HW_LCD();

// SW reset
Write_CMD_LCD(0x01);
DummyWait(3000000); // ~100 ms

// display OFF
Write_CMD_LCD(0x28);

// Power Control B
   Write_CMD_LCD(0xCF);
   Write_DATA_LCD(0x00);
   Write_DATA_LCD(0x81);
   Write_DATA_LCD(0x30);

// Power ON sequence control
   Write_CMD_LCD(0xED);
   Write_DATA_LCD(0x64);
   Write_DATA_LCD(0x03);
   Write_DATA_LCD(0x12);
   Write_DATA_LCD(0x81);

// Driver Timing Control A
   Write_CMD_LCD(0xE8);
   Write_DATA_LCD(0x85);
   Write_DATA_LCD(0x01);
   Write_DATA_LCD(0x79);

// Power Control A
   Write_CMD_LCD(0xCB);
   Write_DATA_LCD(0x39);
   Write_DATA_LCD(0x2C);
   Write_DATA_LCD(0x00);
   Write_DATA_LCD(0x34);
   Write_DATA_LCD(0x02);

// Pump ratio control
Write_CMD_LCD(0xF7);
Write_DATA_LCD(0x20);

// Driver Timing Control B
   Write_CMD_LCD(0xEA);
   Write_DATA_LCD(0x00);
   Write_DATA_LCD(0x00);

// Power control 1
   Write_CMD_LCD(0xC0);
   Write_DATA_LCD(0x26);

// Power control 2
   Write_CMD_LCD(0xC1);
   Write_DATA_LCD(0x11);

// VCOM control 1
   Write_CMD_LCD(0xC5);
   Write_DATA_LCD(0x35);
   Write_DATA_LCD(0x3E);

// VCOM control 2
   Write_CMD_LCD(0xC7);
   Write_DATA_LCD(0xBE);

// Memory access control
   Write_CMD_LCD(0x36);
   Write_DATA_LCD(0x48);

// Pixel format set
   Write_CMD_LCD(0x3A);
   Write_DATA_LCD(0x66); // 18 bit for pixel

// Frame rate control
   Write_CMD_LCD(0xB1);
   Write_DATA_LCD(0x00);
   Write_DATA_LCD(0x10); // 70 Hz

// Enable 3Gamma
   Write_CMD_LCD(0xF2);
   Write_DATA_LCD(0x02); // disable

// Gamma set
Write_CMD_LCD(0x26);
Write_DATA_LCD(0x01);

// Positive Gamma correction
   Write_CMD_LCD(0xE0);
   Write_DATA_LCD(0x1F);
   Write_DATA_LCD(0x1A);
   Write_DATA_LCD(0x18);
   Write_DATA_LCD(0x0A);
   Write_DATA_LCD(0x0F);
   Write_DATA_LCD(0x06);
   Write_DATA_LCD(0x45);
   Write_DATA_LCD(0x87);
   Write_DATA_LCD(0x32);
   Write_DATA_LCD(0x0A);
   Write_DATA_LCD(0x07);
   Write_DATA_LCD(0x02);
   Write_DATA_LCD(0x1F);
   Write_DATA_LCD(0x07);
   Write_DATA_LCD(0x05);
   Write_DATA_LCD(0x00);

// Negative Gamma correction
   Write_CMD_LCD(0xE1);
   Write_DATA_LCD(0x00);
   Write_DATA_LCD(0x25);
   Write_DATA_LCD(0x27);
   Write_DATA_LCD(0x05);
   Write_DATA_LCD(0x10);
   Write_DATA_LCD(0x09);
   Write_DATA_LCD(0x3A);
   Write_DATA_LCD(0x78);
   Write_DATA_LCD(0x4D);
   Write_DATA_LCD(0x05);
   Write_DATA_LCD(0x18);
   Write_DATA_LCD(0x0D);
   Write_DATA_LCD(0x38);
   Write_DATA_LCD(0x3A);
   Write_DATA_LCD(0x1F);

// Column set
   Write_CMD_LCD(0x2A);
   Write_DATA_LCD(0x00);
   Write_DATA_LCD(0x00);
   Write_DATA_LCD(0x00);
   Write_DATA_LCD(0xEF);

// Page set
   Write_CMD_LCD(0x2B);
   Write_DATA_LCD(0x00);
   Write_DATA_LCD(0x00);
   Write_DATA_LCD(0x01);
   Write_DATA_LCD(0x3F);

// Entry mode set
   Write_CMD_LCD(0xB7);
   Write_DATA_LCD(0x07);

// RGB...
   Write_CMD_LCD(0xB5);
   Write_DATA_LCD(0x02);
   Write_DATA_LCD(0x02);
   Write_DATA_LCD(0x0A);
   Write_DATA_LCD(0x14);

   Write_CMD_LCD(0xB0);
   Write_DATA_LCD(0xE0);

   Write_CMD_LCD(0xB1);
   Write_DATA_LCD(0x00);
   Write_DATA_LCD(0x1B);

   Write_CMD_LCD(0xF6);
   Write_DATA_LCD(0x00);
   Write_DATA_LCD(0x00);
   Write_DATA_LCD(0x07);

// Display function control
   Write_CMD_LCD(0xB6);
   Write_DATA_LCD(0x00);
   Write_DATA_LCD(0x80);
   Write_DATA_LCD(0x27);
   Write_DATA_LCD(0x00);

// Sleep OUT
   Write_CMD_LCD(0x11);
   DummyWait(3000000);   // ~100 ms

// Display ON
   Write_CMD_LCD(0x29);
   DummyWait(3000000);   // ~100 ms

//   Write_CMD_LCD(0x2C);   // start memory write...

// construct discriptor array
   for (i=0;i<328;i++)
   {
       // Next Descr Ptr LOW
       // Next Descr Ptr HIGH
       if (i<327)
       {
           LCD_descriptor_array[0+i*9] = (short)( (int)( &LCD_descriptor_array[0+((i+1)*9)] ) & (int)(0xFFFF));
           LCD_descriptor_array[1+i*9] = (short)( ((int)( &LCD_descriptor_array[0+((i+1)*9)] )>>16) & (int)(0xFFFF));
       } else
       {
           LCD_descriptor_array[0+i*9] = (short)( (int)( &LCD_descriptor_array[0] ) & (int)(0xFFFF));
           LCD_descriptor_array[1+i*9] = (short)( ((int)( &LCD_descriptor_array[0] )>>16) & (int)(0xFFFF));
       }

       // Start LINE address LOW
       // Start LINE address HIGH
       if (i<3)
       {
           LCD_descriptor_array[2+i*9] = (short)( (int)( &LCDActivePage[0] ) & (int)(0xFFFF));
           LCD_descriptor_array[3+i*9] = (short)( ((int)( &LCDActivePage[0] )>>16) & (int)(0xFFFF));
       } else
       {
           LCD_descriptor_array[2+i*9] = (short)( (int)( &LCDActivePage[(i-3)*720] ) & (int)(0xFFFF));
           LCD_descriptor_array[3+i*9] = (short)( ((int)( &LCDActivePage[(i-3)*720] )>>16) & (int)(0xFFFF));
       }

       // DMA CONFIG (16 bit)
       LCD_descriptor_array[4+i*9] = 0x7981;

       // X count...
       LCD_descriptor_array[5+i*9] = 741;

       // X modify...
       LCD_descriptor_array[6+i*9] = 1;

       // Y count...
       LCD_descriptor_array[7+i*9] = 1;

       // Y modify...
       LCD_descriptor_array[8+i*9] = 1;
   }

// DMA for PPI...
*pDMA0_CONFIG = 0; // clear DMA0

   *pDMA0_PERIPHERAL_MAP = 0x0000; // connect DMA0 for PPI

   *pDMA0_NEXT_DESC_PTR = &LCD_descriptor_array[9];

   *pDMA0_START_ADDR = &LCDActivePage[0];

   *pDMA0_X_COUNT = LCD_descriptor_array[5];

   *pDMA0_X_MODIFY = LCD_descriptor_array[6];

   *pDMA0_Y_COUNT = LCD_descriptor_array[7];

   *pDMA0_Y_MODIFY = LCD_descriptor_array[8];

   *pDMA0_CONFIG = LCD_descriptor_array[4]; // DMA enable...

asm("ssync;");

// timers for HSYNC and VSYNC...
   *pTIMER_DISABLE = 0xFF;   // all timers - stop...

   *pTIMER_STATUS = 0xFFFF; // all flags - clear...

   *pTIMER0_CONFIG = 0x02B9;

   *pTIMER1_CONFIG = 0x02B9;

// HSYNC
*pTIMER0_WIDTH = 10;

*pTIMER0_PERIOD = 760;

// VSYNC
*pTIMER1_WIDTH = 2*760;

*pTIMER1_PERIOD = 328*760;

// DOTCLK (10 MHz)
   *pTIMER5_CONFIG = 0x0219;

   *pTIMER5_WIDTH = 4; // 4

   *pTIMER5_PERIOD = 8; // 8

   asm("ssync;");

// PPI...
   *pPPI_STATUS = 0;

   *pPPI_DELAY = 19;

   *pPPI_COUNT = 759;

   *pPPI_CONTROL = 0xC01F;   // PPI enable...

   *pTIMER_ENABLE = 0x3|(1<<5); // running...

   asm("ssync;");

ILI9341 via 6-bit RGB mode...

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