Does the STM32F446RE have FMC?

[ibxx0402]

There seems to be conflicting information about FMC support on the STM32F446RE board. As the spec sheet says that it doesn't have support for FMC while the stm32f4 series product page says it has FMC. I have attached some files showing this contradiction. What should I believe in?, the specific board revision is MB1136 C-04 A220702108.

Thanks in advance. 

[mƎALLEm]

Hello,

According to the datasheet: the answer is No.

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@ibxx0402 wrote:

 while the stm32f4 series product page says it has FMC.

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Some STM32F4 part numbers have FMC interface others not.

Regarding, the reference manual, it describes all the feature for that series, but datasheet provides which feature is available on a given part number and which feature is not.

Hope that answers your question.

[ibxx0402]

Thanks for the answer, but the product page says otherwise, it should be shown in the excel file.

[mƎALLEm]

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@ibxx0402 wrote:

Thanks for the answer, but the product page says otherwise, it should be shown in the excel file.

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It could be a typo. I will escalate it internally for fix.

[mƎALLEm]

But referring to the Excel, it is merging all external memory in the same column "External Memory Interfaces" : QSPI and FMC, and QSPI is available on that part number. I think this is the format and could not be changed.

[ibxx0402]

Just to be 100% sure, it doesn't support FMC or FSMC in any capacity right?

[mƎALLEm]

In this product series only FMC is available and not FSMC.

And on STM32F446RE part number FMC is not available.

Hope all is clear now.

[waclawek.jan]

In STM32 older than the 'F4 family and also in the historically first members of the 'F4 family, the external memory module was called initially FSMC, and after adding SDRAM support in newer models it was renamed to FMC.  However, in newer STM32 families ST continued to use the FMC name even if it does not contain SDRAM support. So FMC and FSMC is essentially the same module, and whether it does support SDRAM or not has to be checked per device (in 'F446 it does).

The FMC module *is* present in the STM32F446RE silicon, but almost no signal of it is brought out onto pins of the 64-pin package, so it's entirely unusable. That's why the DS says it's not there as it has no utility in that package. Only in the 100-pin package it gets somewhat usable, and full usability is only in the >144-pin packages.

JW

 

[ibxx0402]

I might also be able to get my hands on a stm32f407 which should have proper support for FSMC, Would that be usable for external flash memory?

[waclawek.jan]

As I've said above, FMC is a superset of FSMC, so FMC in 'F446 has the same functionality as FSMC (and it has SDRAM support).

And, as I've said above, it's the package (number of pins) which matters, so if the 'F407 is in 64-pin package, its FSMC is unusable in the same way as in the 64-pin 'F446.

JW

[ibxx0402]

I am not sure if the one I can get a hand on is the 64 pin version or one with more pins. But i was told that the boards would be similar so I would guess that they both have 64 pins. But nonetheless it seems like the data sheet says that FSMC is supported on all F407 boards. I have attached the sides from the data sheet. 

[mƎALLEm]

It depends on which package you are using.

As stated by the image you shared from the datasheet STM32F407RG doesn't have FSMC.

But becarefull some other packages like LQFP100 have FSMC but not all signals (FSMC_A0 to FSMC_15) are exported externally but you need to use FSMC in mux mode (data and address lines from 0 to 15 are muxed).

You can address LCD over FSMC as it is but with an external memory you need one that supports natively the mux mode or add an external HW (for address latch) to allow this connection.