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alivexiaoluo
alivexiaoluo
Associate III
February 26, 2020
Solved

How to choose QSPI Flash(nor flash or nand flash)and ram on stm32h7b0vb is enough for custom design?

  • February 26, 2020
  • 14 replies
  • 6446 views

Hi,

I have a project under EVT situation.

I will choose the stm32h7b0vb(128K Flash + 1.18M SRAM)as the mcu for the system.

The main functions is below：

1,Driver a tft-lcd with touch via LTDC interface,lcd size is 640*360 pixes support rgb888 and support single touch and slide.

2,Support FreeRT OS and about 10 tasks.

3,8M Bytes for sampling data record​s storage in flash and 40K SRAM for data records write and read.

4,Support DFU via ble(OTA), stm32h7b0 connect ble soc via uart.

Q1:

If the QSPI Flash is used for code storage and sampling data records storage,which one should be optimized(nor flash or nand flash)?What is the difference between the nor flash and nand flash?

Q2:

The SRAM on stm32h7b0 chip is enough for software design?

Q3:

How to design the dfu when use extern QSPI Flash for code storage?(I designed the dfu on internal flash on stm32f103re )

Thanks for your attention.

This topic has been closed for replies.
Best answer by Martin KJELDSEN

I'll answer the first two, at least.

Q1. NAND flash is not memory mapped. If TouchGFX cannot access the data in your flash using a simple pointer, then you need to cache your images using a driver that you create - This leads to performance overhead and slightly convoluted view code (because of constant caching, uncaching of images)

Q2. You can do some calculations to figure out of the SRAM on the H7b0 is enough for you. It really depends on what else you need your application to do. Example: 480*272*3=326.400 bytes for a single 24bpp application framebuffer.

/Martin

14 replies

Martin KJELDSEN
Martin KJELDSENBest answer
Principal III
February 26, 2020

I'll answer the first two, at least.

Q1. NAND flash is not memory mapped. If TouchGFX cannot access the data in your flash using a simple pointer, then you need to cache your images using a driver that you create - This leads to performance overhead and slightly convoluted view code (because of constant caching, uncaching of images)

Q2. You can do some calculations to figure out of the SRAM on the H7b0 is enough for you. It really depends on what else you need your application to do. Example: 480*272*3=326.400 bytes for a single 24bpp application framebuffer.

/Martin

alivexiaoluo
alivexiaoluoAuthor
Associate III
February 26, 2020

Hi,Martin KJELDSEN.

So if I want ​better display effect，we should use nor flash.

I want to know if the nand flash fit for my design? Is it very inconvenient for developing TouchGFX on nand flash？

Thanks for your attention.

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