how to use FMC NOR flash to store touchgfx assets such as images, fonts, text etc while the frame buffer is located in FMC SDRAM ?

[sanjeev majumdar]

..

[Tesla DeLorean]

Do you have either memory working currently?

​

From the build perspective you'd need to describe the memory regions in the linker script, and direct objects to be placed into those sections.​

[sanjeev majumdar]

HI clive1,

thank you for your response. Yes i have both the memories working in. i am able to execute data transaction with FMC NOR flash and on the other hand able to use FMC SDRAM as frame buffer. As per your suggestion i have defined the memory regions in linker script and also placed the assets in NOR flash but the issue is the images are not getting retrieved properly while displaying screens using touchgfx. over all i can say that at a time images are not getting displayed when they are located in NOR flash and when i touch the screen at the position of image it flickers and goes back. What i can understand that at a time i am not able to access both memories sitting on FMC bus. If you can help me any example where both the memories are used for touchgfx. All ST given examples use QUADSPI flash for assets than FMC flash. Also i find this in the reference manual : "All external memories share the addresses, data and control signals with the controller.

Each external device is accessed by means of a unique Chip Select. The FMC performs

only one access at a time to an external device."

[sanjeev majumdar]

Hi,

Can anybody share an example where FMC NOR flash is used to store the Touchgfx assests while frame buffer is located in FMC SDRAM ?

[sanjeev majumdar]

Anyone? @Martin KJELDSEN (ST Employee)​ @Romain Dieleman (ST Employee)​ 

[sanjeev majumdar]

can anyone tell me, is it feasible to store Touchgfx assets in FMC NOR flash and maintain frame buffer in FMC SDRAM or do i have to use QSPI flash only ?

[sanjeev majumdar]

@Martin KJELDSEN​ do i have to use QSPI flash only for touchgfx assets or can i use FMC NOR flash, if yes can you plz share an example

[waclawek.jan]

> when i touch the screen at the position of image it flickers and goes back

If - as you say - both the NOR FLASH and SDRAM work separately OK, I wouldn't be surprised if you would simply be exhausting the available FMC bandwidth. To display any resorce from the NOR FLASH, the processor needs to move all data from the NOR FLASH to the processor's registers, and then back to SDRAM; at the same time it needs to move data from the SDRAM to LTDC to display them.

It may quite well be that there's no solution to this and you'd need to choose an entirely different hardware; this depends of course on the resolution of the display, refresh rate, color depth, bus width of both SDRAM (is it 32-bit?) and NOR FLASH, and the particular items you want to display. Generally, for resolutions above QVGA (320x240) you are better off using something much more powerful e.g. the Raspberry Pi.

JW

[sanjeev majumdar]

thanks for the reply. I will try some more experiments and consider using qspi flash instead of FMC flash.

[Martin KJELDSEN]

@sanjeev majumdar​  - I don't have a concrete example of FMC + NOR Flash - But i'm sure you'd be able to find something in the Cube firmware examples/projects.

You can use any type of storage you want. If you're not using memory mapped flash then you have to use bitmap or font caching to use assets in your application. I can show you that, at least.

/Martin

[sanjeev majumdar]

Hello Martin,

There is no example available for FMC NOR flash used to store touchgfx assets in cube firmware examples/projects. Only i could find examples where QSPI flash is used for touchgfx.

I have done necessary initialization for FMC NOR flash and also described the Flash memory region in the linker script as follows, but it dint work. I am using stm32f769i eval board for the same. FMC nor flash is memory mapped. Also i have taken care the caching part using mpu config for nor flash and in sdram. kindly let me know where could be the issue.

 LR_ROM1 0x60000000 0x01000000 {  ; load region size_region

 extflash.bin 0x60000000 0x01000000 { ; load address = execution address

  *.o (ExtFlashSection)

 }

 }