STM32U5A9J-DK: Init the MIPI-DSI TFT round LCD from the scratch, (without touchgfx and default code)

[emmaulala]

I am coding from the scratch to learn how STM32 works with MIPI-DSI LCD, because I am going to use customized MIPI-DSI LCD. I refer to the official code, but some incorrect content as below:

official default code: in main.c , static void MX_LTDC_Init(void):

// SETVCOM

uint8_t InitParam60[4] = {00, 00, 00, 0xC0};

if (HAL_DSI_LongWrite(&hdsi, 0, DSI_DCS_LONG_PKT_WRITE, 4, 0xC7, InitParam60) != HAL_OK)

{

Error_Handler();

}

BUT, I check HX8379C datasheet (LCD control ), SETVCOM command is (B6h), and there is no 0xC7 command ?

so what's this code for? and HX8379C datasheet dosen't mention initial sequence , how do we know that we need to set SETPOWER, SETDISP, Set display cycle timing,.....SET GAMMA,....,then Exit Sleep Mode to let LCD work? 

I don't use touchgfx now, just want to test if DSIHOST, LTDC work successfully, so I declare a framebuffer[480*480] then in MX_LTDC_Init(), write:
pLayerCfg.FBStartAdress = (uint32_t)framebuffer;
then using for loop to fill it red, but the screen is still black

[Saket_Om]

Hello @emmaulala 

---

@emmaulala wrote:

I refer to the official code, but some incorrect content as below:

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Could you please specify the name of the example you are referring to?

[emmaulala]

@Saket_Om 

These 2 examples contains what I mentioned incorrect: the example from touchGFX Designer of STM32U5A9J-DK, in main.c , in function  MX_LTDC_Init, and the example from firmware package (\Repository\STM32Cube_FW_U5_V1.8.0\Projects\STM32U5x9J-DK\Examples\DSI\DSI_VideoMode_SingleBuffer), in main.c, in function SetPanelConfig, what's 0xC7 cmd for?

BTW, I refer to VideoMode_SingleBuffer example, and I succeed in displaying on the screen, and now I turn on ThreadX and touchGFX, and follow the instruction (https://support.touchgfx.com/docs/development/touchgfx-hal-development/scenarios/scenarios-dsi-video-mode), and I keep singlebuffer location 0x200D0000 with touchgfx, after turning on LTDC interrupt, I succeeded!