What's an STM32GC102CB ? - Page 1
Forum section: electronics / general

author: gertux
author_rank: Contributor
timestamp: December 31, 2018, 12:46:59 pm
content: Just wondering if anyone has ever seen a STM32GC102CB ? Like the left one in the image below.I've bought several ST-Link clones over the years and they used to come with a STM32F101CBT6, but last November I received one with a STM32F102CBT6 (right one in the image below)Today I received one with STM32GC102CB markings which is as far as I can tell not an STMicroelectronics part number.

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: December 31, 2018, 01:25:26 pm
content: A wild guess, but maybe it is a "Gigadevices Clone"? Gigadevices make a legitimate clone of the STM32F102, but marking it is an ST product is counterfeiting.

author: JPortici
author_rank: Super Contributor
timestamp: December 31, 2018, 01:53:15 pm
content: This came out in the STM32 facebook group too..we already have the STM32G0 series ->https://www.st.com/en/microcontrollers/stm32g0-series.html?querycriteria=productId=SS1960and between all those who cried fake fake one user hinted that the g1 family is due to come out soon

author: gertux
author_rank: Contributor
timestamp: December 31, 2018, 03:37:22 pm
content: Quote from: JPortici on December 31, 2018, 01:53:15 pmIs indeed a possibility, I would expect an STM32G102CB, without the C after the G, but then again everything is possible with STM product names.

author: Yansi
author_rank: Super Contributor
timestamp: December 31, 2018, 04:14:13 pm
content: Meep.Bookmarking the topuc. Will ask our MCD division colleagues what that is, once I get to work.

author: andersm
author_rank: Super Contributor
timestamp: December 31, 2018, 04:22:11 pm
content: Try connecting to its JTAG/SWD interface and read out the chip ID.

author: gertux
author_rank: Contributor
timestamp: December 31, 2018, 04:39:26 pm
content: Quote from: andersm on December 31, 2018, 04:22:11 pmOk I’ll do that but not today, we’re heading out to a new years party in 8 minutes.Will post as soon as I have had the chance to check.

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 31, 2018, 04:44:58 pm
content: Quote from: gertux on December 31, 2018, 03:37:22 pmYeah, it would probably not be marked "STM32GCxxx".Interestingly, there are questions about this exact reference on chinese forums back in 2011, so I highly doubt it's a new model due to come out soon.Eg:http://bbs.eeworld.com.cn/thread-254285-1-1.htmlYou can also find references of it on Aliexpress. It apparently used to be available there but is now marked as unavailable.http://www.aliexpress.com/item//32655847283.htmlI don't understand chinese but used Google translate to get an idea. Someone seems to hint that it may have been a part made from a collaboration between STM and the Chinese Academy of Sciences.Maybe some of the regular here from China have more info about this?

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 01, 2019, 05:11:12 pm
content: Quote from: blueskull on January 01, 2019, 06:31:39 amOK, thanks for the info. Considering that this reference appeared years ago on the chinese market and isn't referenced anywhere at STM, it's probably just an STM32 clone, isn't it?

author: gertux
author_rank: Contributor
timestamp: January 01, 2019, 08:17:58 pm
content: Quote from: andersm on December 31, 2018, 04:22:11 pmWhen I run st-util with the device connected using SWD, I get:Device connected is: F1 Medium-density device, id 0x20036410SRAM size: 0x5000 bytes (20 KiB), Flash: 0 bytes (0 KiB) in pages of 1024 bytesChip ID is 00000410, Core ID is 1ba01477.

author: andersm
author_rank: Super Contributor
timestamp: January 01, 2019, 09:31:12 pm
content: The flash size is obviously bogus, but the device id looks OK (medium-density device, revision 1, 2, 3, X, or Y, which matches the revision code in your photo). Maybe a factory reject that failed testing before the flash size was burned?

author: Yansi
author_rank: Super Contributor
timestamp: January 01, 2019, 11:05:45 pm
content: Quote from: gertux on January 01, 2019, 08:17:58 pmDevice ID 0x410 is STM32F1, medium density silicon (102/103, 64/128kB FLASH). Nothing to write home about.The GC code is interesting though, but I'd say it may be a custom batch for some larger customer, being special in some way compared to the regular ones. Now the chinese STLINK cloners are using these, due to probably having a lot of them in stock left.//EDIT: Also, "strange" letters may appear (typically as a suffix) to denote HW locked licenses for SW solutions burnt in the system flash.I will ask our MCD team tomorrow.

author: JPortici
author_rank: Super Contributor
timestamp: January 03, 2019, 06:57:34 am
content: Quote from: Yansi on January 01, 2019, 11:05:45 pmMaybe the absence of flash?

author: tsman
author_rank: Frequent Contributor
timestamp: January 03, 2019, 02:22:02 pm
content: Quote from: JPortici on January 03, 2019, 06:57:34 amThere must be flash inside or it wouldn't work as a ST-Link/V2. A ST-Link/V2 needs 64KB of flash so it shouldn't be any less than that. There is a memory location you read that tells you the amount of flash in a STM32 but I've no idea why it reports 0.

author: JPortici
author_rank: Super Contributor
timestamp: January 03, 2019, 08:26:10 pm
content: My extremely wild guess is that C = OTP or mask rom, so technically no flash, programmed with an usb bootloader and the st-link code is loaded in ram by the applicationbut i'm just blabbering at this point

author: tsman
author_rank: Frequent Contributor
timestamp: January 03, 2019, 08:59:02 pm
content: Quote from: JPortici on January 03, 2019, 08:26:10 pmThat would make it incompatible with ST-Link apps as none of them expect to upload the firmware before usage.Digging around on a Chinese forum, somebody says the STM32GC102CB is actually a STM32F102CB for development purposes but there is a difference in the USB support. The short excerpt of an translated English datasheet is also there where it says that is a low density device which officially only has 16K/32K flash and 6K RAM. The datasheet doesn't quite match up with the statement it is a STM32F102CB but in reality I suspect it is true since they're able to use the STM32F103 ST-Link/V2 code on it. The datasheet saying low density is strange since OP's STM32GC102CB reports medium density.I'm guessing it is the same situation as the STM32F10xCxs that all share a die and all have the USB controller anyway. 90% of the time they come with 128K flash but I do have some that only have the official 64K.My guess is that this STM32GC102CB is some weird low cost variant because of excess chips or chips that failed testing. The ST-Link/V2 clones have a tradition of using the wrong part to save money. STM32F100C8s instead of STM32F103s etc...

author: Yansi
author_rank: Super Contributor
timestamp: January 05, 2019, 10:54:55 am
content: I have pushed the question to our MCD team. The guys at the playce I work didn't know about that (we specialize only on certain lines and part numbers). Now we wait.

author: gertux
author_rank: Contributor
timestamp: January 06, 2019, 01:07:32 pm
content: Some extra info, may be useful.I've unlocked the flash using:Code:openocd -f interface/stlink-v2.cfg -f target/stm32f1x.cfg -c "init" -c "halt" -c "stm32f1x unlock 0" -c "shutdown"After I power cycled the device it now reports 64KiB flash using st-util:Code:Device connected is: F1 Medium-density device, id 0x20036410SRAM size: 0x5000 bytes (20 KiB), Flash: 0x10000 bytes (64 KiB) in pages of 1024 bytesChip ID is 00000410, Core ID is 1ba01477.

author: Kjelt
author_rank: Super Contributor
timestamp: January 06, 2019, 06:50:59 pm
content: I don't know how long a NDA is valid but I am already waiting a long time for ST to break newshttps://www.eevblog.com/forum/microcontrollers/stm32g-series/msg1256007/#msg1256007

author: Kjelt
author_rank: Super Contributor
timestamp: January 06, 2019, 06:53:10 pm
content: And what is this abouthttps://www.elnec.com/en/products/programming-adapters/DIL48_QFN48_ZIF_STM32G-1/

author: krho
author_rank: Regular Contributor
timestamp: January 06, 2019, 06:54:13 pm
content: TheSTM32G seriesis already out.. It was announced about a month ago. it's 64MHz M0+. With USB-C PD hardware. IMO this it's going to be used a lot for that.

author: JPortici
author_rank: Super Contributor
timestamp: January 06, 2019, 06:55:31 pm
content: Quote from: Kjelt on January 06, 2019, 06:50:59 pmhttps://www.st.com/en/microcontrollers/stm32g0-series.htmlQuote from: krho on January 06, 2019, 06:54:13 pmYes, i think i opened a thread when i saw the newsletter. I seem to remember that there is the controller but not the PHY for usb C, am i right?

author: Kjelt
author_rank: Super Contributor
timestamp: January 06, 2019, 07:11:40 pm
content: A good so no more secrets

author: tsman
author_rank: Frequent Contributor
timestamp: January 06, 2019, 07:31:30 pm
content: Quote from: Kjelt on January 06, 2019, 06:50:59 pmIt isn't this. STM32GC102CB has been around for years now but only mentioned in Chinese only forums. It isn't the STM32G0xx that was recently announced.

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 06, 2019, 08:08:06 pm
content: Quote from: tsman on January 06, 2019, 07:31:30 pmYes, as I said above.And IMO there is no way the new MCU line could have 1/ already appeared in chinese products at this point, especially on cheap clones, 2/ be a drop-in replacement MCU for a ST-LINK/V2, which uses a Cortex-M3, whereas the new G0 line is a M0+, and 3/ again "STM32GC" makes no sense as far as STM marking goes. The new STM32G0 MCUs are marked "STM32G" on the first line on the chip packages, and the numbering on the second line.AFAIK, official STM's marking scheme has been like this for a long time: STM32x on the first line, with x a letter indicative of the series (such as STM32F, STM32L...) and then the second line is the numbering (such as 103yyy, 433zzzz... etc)So IMO, either it was some kind of clone, or some kind of prototyping batch from STM that has leaked from some chinese plant. Would be interesting to have the opinion of STM on this one though...

author: tsman
author_rank: Frequent Contributor
timestamp: January 06, 2019, 08:58:40 pm
content: Quote from: SiliconWizard on January 06, 2019, 08:08:06 pmIt would be strange to go to the hassle of cloning a STM32F1 but then still call it a STM32 but change the family to GC. You'd either make your own range or also copy the F family designation. The GD32 devices are clones but they're marketed as a GigaDevices product and completely different inside.My guess is still that they're a custom STM32F1 made for somebody and old/excess stock has been sold off. The ST-Link cloners were already pennypinching by using STM32F100s which don't officially have USB.A while ago, somebody asked ST if the incredibly cheap STM32s available from China were counterfeit or real. ST said that there aren't any fake STM32s and that they're all real. They didn't explain why they were so cheap even compared with the bulk order pricing in China. Somebody must be buying a crazy number of these uCs.

author: Yansi
author_rank: Super Contributor
timestamp: January 06, 2019, 09:53:19 pm
content: There is a huge market for STM32 and STM8 chips in china, as many of you already noticed them in many products from there already.I can assure the prices, which these parts sell in large quantities (100ku or 1MU) are tiny compared to what those money hungry distributors often want from you, as an individual.

author: amyk
author_rank: Super Contributor
timestamp: January 06, 2019, 10:20:32 pm
content: Quote from: tsman on January 06, 2019, 08:58:40 pmSo the USB controller is present, not officially advertised as working, but often it does? Interesting...

author: ataradov
author_rank: Super Contributor
timestamp: January 06, 2019, 10:23:28 pm
content: Quote from: amyk on January 06, 2019, 10:20:32 pmThis happens very often. Probably all MCUs on the market have peripherals/features that are not advertised. Often this means that they are not fully compliant. But that's not a big deal for random Chinese manufacturers that never intended to pass compliance test anyway.

author: Yansi
author_rank: Super Contributor
timestamp: January 06, 2019, 10:30:02 pm
content: It is way easier than that. It is more cost effective to manufacture less types of dies and market these as multiple devices. It does not even pay off to split the manufacturing line at the chip level, so peripherals may get disabled/blocked on chip level. The only split in the manufacturing process is at the part labeling.However, no-one will assure you, that your STM32F102 will have working USB all the time in any way shape or form. It has already happened changes have been made, manufacturing further optimized, so these "hacks" have stopped working suddenly.The only peripherals that do get really blocked, are those that must conform to stupid export laws, so for example cryptography. You know, some states like Russia and the US of A does not like people to encrypt their properties too freely.

author: tsman
author_rank: Frequent Contributor
timestamp: January 06, 2019, 10:38:09 pm
content: Quote from: Yansi on January 06, 2019, 10:30:02 pmYep. Same deal with the "bonus" flash on some of them. It definitely isn't guaranteed in any way but a lot of people rely on it now which is a bad idea for production.

author: Yansi
author_rank: Super Contributor
timestamp: January 06, 2019, 11:26:21 pm
content: It is not a bad idea, it is a very bad one. Neither is it guaranteed to work at any time, nor will STMicro give you any support if problems occur. It is solely your responsibility, if you are bending the rules.It may be fun for homebrewers, but definitely not for production.

author: langwadt
author_rank: Super Contributor
timestamp: January 06, 2019, 11:44:22 pm
content: Quote from: tsman on January 06, 2019, 10:38:09 pmYeh a place I worked someone accidentally used a section of RAM in DSP that wasn't supposed to be there but it worked because it was thesame die as a part with more ram, one day production stopped because nothing worked.- The company making the chip had enough volume of the reduced ram version that they had spun a new chip that only had the specified RAM

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 07, 2019, 02:10:18 am
content: Quote from: tsman on January 06, 2019, 08:58:40 pmDepends on what kind of "cloning" you consider. Redesigning a functionally-equivalent chip would be a hassle, but OTOH you just need to have gotten ahold of genuine bare dies one way or another. A few wafers may have gotten lost...The packaging itself may be done in any chinese plant that would add the marking they want. That happens.Quote from: tsman on January 06, 2019, 08:58:40 pmI also suggested genuine "prototypes" - that could be custom-made chips as well indeed. But I don't know STM's policies when it comes to custom versions of their MCUs. I don't know if they do it. If it's the case here, using/selling custom-made chips for any other use than what was granted by STM is probably illegal anyway.As to the pricing they have for different markets, it's not surprising. Many companies do that (especially for developing countries markets), and further deals with companies buying in huge volumes is common. Of course they are going to be secretive about the details. This is confidential business information. STM32 MCUs have a significant market share in China, and this is an extremely competitive market, so they have probably done what needed to be done to get there...