STM32H730ZB - LTDC RGB888 - some output not controlled by LTDC

[COSEBE]

I have a custom board with a STM32H730ZB

I use a LCD 1024x600 controlled by LTDC.

Here is the pinout :

here is the config :

When executing code :

I break just after the HAL_LTDC_INIT function.

I should have a white screen (R=255, G=255, B=255)

But I have a strange color !

So I testes each bit of R[7..0] G[7..0] B[7..0] by modifying register :

 BCBLUE, BCGREEN and BCRED

Every bit works except

LCD_R7, LCD_B7, LCD_B6 and LCD_B4

Of course, my first thinking is a hardware problem..... but no

I focus on LCD_R7 :

1st test:

If I change LCD_R7 pin on PC4 in source code to OUTPUT_PP instead of ALTERNATE and set it to 1, the LCD draw the red background (I set all others bits to 0) => the color is 0x800000

==> So no hardware problem and LCD is OK

2nd test:

I move the LCD_R7 from PC4 to PG6, and the LTDC drive LCD_R7 correctly

==> So LTDC can drive LCD_R7 on PG6 (pin 91) but NOT on PC4 (pin 44)

Why those 4 pins are not drive correctly by LTDC on STM32H730ZB ?

[COSEBE]

Please check this post:

 

https://community.st.com/t5/stm32-mcus-products/stm32h730zb-octospi-cannot-write-dcr1-register/td-p/689870