STM32F746-DISCO FMC/LTDC pin configurations Topic is solved

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cpu20
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STM32F746-DISCO FMC/LTDC pin configurations  Topic is solved

Postby cpu20 » Fri Apr 28, 2017 5:10 pm

Hello,
- I have been debugging the problems that occurred while using uGFX together with ChibiOS on the STM32F746-DISCO platform.
After allot of searching I have come to the conclusion that the problem is located in the pin configurations. Two pins are configured differently than expected.
- This is with ChibiOS_16.1.7
- Compiled with gcc-arm-none-eabi-5_4-2016q2
- The problem is that the pins PG8/FMC_SDCLK standard is configured as input floating. But for the SDRAM on the board to work this pin should be configured as FMC_SDCLK (alternate function 12).
The second problem is that the pin PI12/LCD_DISP_PIN is configured as LCD_HSYNC by setting it to alternate function 14. But this pin should be configured as a normal highspeed output.
A last problem is that the LTDC clock is configured to 48MHz (display takes 12-20MHz max) in the mcuconf.h included in the demo code. This can easily be fixed by setting STM32_PLLSAIDIVR to STM32_PLLSAIDIVR_DIV4, changing the clock to 12MHz.
- The effect of these two pins being wrongly configured is the whole display not working. Setting these correctly in the board files (attached) makes the display work!
Patched files should be included.
Attachments
PatchedChibiOSFiles.zip
(15.71 KiB) Downloaded 114 times

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Re: STM32F746-DISCO FMC/LTDC pin configurations

Postby Giovanni » Mon May 29, 2017 10:49 am

bump

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Re: STM32F746-DISCO FMC/LTDC pin configurations

Postby Giovanni » Tue May 30, 2017 7:56 am

Hi,

I committed the fix in trunk and will be released as 17.6.0, note that mcuconf.h settings changed a bit. This will not be backported to 16.1.x.

Giovanni

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Re: STM32F746-DISCO FMC/LTDC pin configurations

Postby cpu20 » Tue May 30, 2017 6:40 pm

That is very good news!
Thanks for committing the fix!


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