ART-PI dev board STM32H750 FMC+LTDC+RGB888 display

[Thomas8607]

Hi all!

I wrote code on my ART-PI development panel that displays a simple filled box and text (touchgfx). I use the following in both projects:
FMC with 240Mhz, SDRAM with 120Mhz. W9825G6 data 16bit
CPU clock 480Mhz
RGB888 display, MRG7122 DCLK typical clock signal 51.2Mhz, maximum 67.2Mhz

I made two projects.
First, the peripheral initializations in the main.c file. Display works on 50Mhz.
In the second project, I checked at the beginning that the peripheral initializations should be in separate files. The maximum ltdc clock here is 27.5Mhz, above which the display crashes.

Why if all other settings are the same? Where should I look for the reason?

Thanks!

[Thomas8607]

Clock configurations.

[Tesla DeLorean]

I'd probably write code to unpack the run-time configuration of the clocks and PLLs, and confirm they are actually as expected.

Order is perhaps also important, and if other things are changing the PLL / Peripheral settings later during initialization.

[Thomas8607]

If I look at the clock on the display with oscilloscope, does this show up? Could it be a double clock? Because 2x 27.5mhz is above the maximum display clock.

Thanks! 

[Thomas8607]

I've seen with oscilloscope, the clock is good.

[Thomas8607]

I'm ***. It was user error :(
I forgot enable the burst in sdram configuration.

Please close this topic.

[Tesla DeLorean]

2x27.5 is less than the 63MHz ceiling on the display in this mode. Not sure if these panels allow for a lower frame rate. Might be an option for lower 4:3 type resolution from 16:9 normal.

As you indicate an issue with the SDRAM could cause random colour field

[Tesla DeLorean]

Which connector on the panel is supposed to be used for the ART-PI cable?

[Thomas8607]

I don't understand your question. Which cable? For what?

[Tesla DeLorean]

The panel has two connectors, atomic / wildfire, which one is used for the ART-PI ??

http://www.lcdwiki.com/7.0inch_RGB_Display