TouchGFX LTDC Framebuffer Address for 800x600 Display with External eMMC (IS21ES08GA-JQLI)

[siddum]

Hello ST Community Team,

We are currently working on an STM32N6-based design using TouchGFX and would appreciate your guidance regarding the LTDC framebuffer address configuration.

Setup details:

• Display resolution: 800 × 600

• Graphics framework: TouchGFX

• External memory device: eMMC – IS21ES08GA-JQLI

• The eMMC is used as external memory in the system

While configuring TouchGFX and LTDC, we need to specify the framebuffer start address for the LTDC layer. Since the framebuffer is not located in internal SRAM, we would like to understand:

1. What LTDC framebuffer address should be provided when using an external eMMC (IS21ES08GA-JQLI)?

2. Is it recommended (or required) to first map the framebuffer into an external RAM (such as SDRAM/PSRAM) instead of directly using eMMC?

3. Are there any reference examples or application notes showing TouchGFX with LTDC using external eMMC for framebuffers?

Any clarification on the correct memory mapping and recommended architecture for this use case would be very helpful.

Thank you in advance for your support.

Best regards,
Marka

[tdecker2]

Framebuffer must be in RAM, either internal or external. eMMC is flash not RAM.The flash can be used to store graphics and fonts, TouchGFX renders them into the framebuffer and LTDC sends that data to the display.

Not familiar with the N6-Family, but some of them should have enough internal RAM for the framebuffer (with RGB565 you need 800 x 600 x 2bytes=960000 bytes).