Chinese STM32F407VET6 Fakes?

[chuck guzis]

I've got a few of the Aliexpress Chinese STM32F407VET6 development boards that arrived recently. I became suspicious when the content of 0x1FFF7A22 is reported as 0xffff, when it should be the flash size in KB. The MCU chip itself reads:

STM32f407

VET6

991ES 9R

MYS 99 145 4

ST e3 ARM

04

Note that there's no revision number, which immediately made me suspicious. The MCU at first blush, seems to work okay, but what should I be aware of if I should try to use it?

Thanks!

Chuck

[Tesla DeLorean]

A picture would help, high resolution, in focus

The ES is suggestive that it is an Engineering Sample, which would explain the OTP not being programmed.

It is not out of the French Fab

The "4" is a valid marking, and consistent with the mask set / fab

[chuck guzis]

Here's a photo. I also have some with the 06 marking. What perplexes me is the 0xffff read from the flash size register. It also seems to confuse OpenOCD, which defaults to 1024K flash size. A known-valid STM32407VET6 reads 0x200 in the same location.

[chuck guzis]

I'm wondering if these are re-labeled CETC CKS32F407VET6 chips.

https://www-sekorm-com.translate.goog/news/42433110.html?_x_tr_sl=zh-CN&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=sc

[AScha.3]

just try ... i had a CKS32F103 -- and made a test loop on ADC sampling; surprise: it was better than the "original" STM32F103 . (otherwise was same as STM , as far, as i tested.)

so not all "fakes" are fakes, maybe just "pin and function compatible" chips from another source.

(my chips also labeled CKSxx .)

[Tesla DeLorean]

This has different markings than you mentioned earlier.

Does this have the boot loader and Flash size as 0xFF ?

The OpenOCD app should identify the Core, and that's usually different for CKS vs ST

[Tesla DeLorean]

That link doesn't translate/work here.

Try https://www.sekorm.com/news/42433110.html

In STM32 Cube Programmer, what does the memory at 0x1FFFF000 look like?

[chuck guzis]

Don't use STM32 Cube, but I'll jot down some C code and get back to you.

[chuck guzis]

The type font looks more like what one sees on the Gigadevice GD32F407VET6--sort of an OCR-A.

What with the chip shortage, I wonder how many "clone" manufacturers are taking advantage of the situation...

[chuck guzis]

On the one I initially reported:

openocd reports Info : device id = 0x10076413

memory at 0x1FFFF000: 0xffffffff

flash size = 0xffff

On the one in the photo, same device ID, but flash size register is 0x200.

I'll attach a photo of the one I initially reported a bit later...

I should note that both came from the same shipment.