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

[alivexiaoluo]

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.

[Tesla DeLorean]

QSPI is not really setup to do concurrent operations well. NOR flash is very slow to erase/write, and NAND isn't any good for code execution.

Ideally you'd pull resources from NAND as block(s) and not waste hundreds of KB staging things.

I'd recommend getting experience of the technologies before jumping into implementation.

I'd use dual banked QSPI NOR for XIP code, and eMMC for NAND storage

[alivexiaoluo]

So your suggestions is that I should use nor flash instead of nand flash for code storage and code running, and if the UI components is too big I should use eMMC for nand storage?

Thanks for your attention.

[Tesla DeLorean]

I'm saying that's how I'd approach the problem. It leverages the features of the MCU, removes wear management and ECC issues, and uses devices that could be sourced for several years.

Not sure what NAND device you're proposing that supports XIP

Doing code overlays in SRAM could be done, but seems unnecessary, and the tool chains don't really facilitate that well.

[alivexiaoluo]

Hi, clive​1.

You misunderstand my intention, and there is no nand flash supports XIP.

I am trying to find a solution to replace nor flash with nand flash for cost down, and if the tool chains can not allocate different address for code(functions) and ui components(const data) on extern QSPI flash, the solution can not works.

Thanks for your attention.

[Martin KJELDSEN]

I did it in my head. I'll use a calculator next time.