New Blue Pill forum - Page 1
Forum section: electronics / general

author: GranpasScopes
author_rank: Newbie
timestamp: March 25, 2019, 07:18:34 pm
content: I am very sad to learn that stm32duino is going offline. It does not seem that it allows new signups?So is there a new forum that (can) fills in for stm32duino?I am also interested in purchasing some Blue Pill boards from Ali but have concerns that these STM32C103 boards from Ali might be DOA as this talks about:https://www.kickstarter.com/projects/korishan/honest-stm32f103c-breadboard-pcbIf there are some Ali sellers that are known to sell known good or bad boards, I would really appreciate some tips!

author: martinayotte
author_rank: Regular Contributor
timestamp: March 25, 2019, 07:31:20 pm
content: Quote from: GranpasScopes on March 25, 2019, 07:18:34 pmAn alternative site has been created :https://mcu.selfip.com/

author: thm_w
author_rank: Super Contributor
timestamp: March 26, 2019, 10:55:46 pm
content: Quote from: GranpasScopes on March 25, 2019, 07:18:34 pmInteresting I would buy some but it says ships to US only. Would be very impressed if they can be built for $3/board. Hand assembly, and presumably some testing, will be hell.Quote

author: OwO
author_rank: Super Contributor
timestamp: March 27, 2019, 06:57:16 am
content: Quote from: GranpasScopes on March 25, 2019, 07:18:34 pmThat is simply pure FUD being spread for his own profit. When I lived abroad I bought many $2 stm32f103 boards from different sellers on aliexpress and never encountered any defects. You just need to pay attention to the seller's ratings. I'm willing to bet that guy is just buying from aliexpress and reselling for a profit.

author: tsman
author_rank: Frequent Contributor
timestamp: March 27, 2019, 07:10:30 am
content: What OwO said. The main problem I've had with the dirt cheap Bluepill boards is that USB connector on some of them could do with additional solder for mechanical strength. Some people say you need to replace the USB pull up resistor as its not correct but its always worked fine for all the computers I've tried it on so YMMV.They're buying boards with a STM32F103C6 fitted if they're only getting 32KB of flash. Pay more attention to the item page and make sure it says STM32F103C8 if you need 64KB with a decent chance of an unofficial 128KB. If it still comes with a STM32F103C6 then make a claim on AliExpress for a refund.

author: castingflame
author_rank: Regular Contributor
timestamp: March 27, 2019, 07:39:17 am
content: I have purchase over 50 Blue pills from Ali from 6 or 7 sellers. Not a single problem. In fact my last order for 20 worked out at £1.25 delivered. They came in 3 weeks.As stated, the USB resistor is a known issue but at this point do not use USB.Sent from my SM-N960F using Tapatalk

author: castingflame
author_rank: Regular Contributor
timestamp: March 27, 2019, 08:39:47 am
content: Additionally, the differences between the BluePill and the BlackPill (hobby Electronics original design I believe) is listed in the wiki.https://wiki.stm32duino.com/index.php?title=Black_Pill. Both have the same MCU. AFAI remember the 64/128 flash memory may be down to the chinese sellers using part faulty chips. They are normally advertised as 64K but I have yet to find one that does not program okay as 128K. I guess it depends on your application what choices you make and tests you do.

author: tsman
author_rank: Frequent Contributor
timestamp: March 27, 2019, 08:54:58 am
content: The parts aren't faulty or counterfeit for that matter. ST are/were making dies with 128KB flash and selling them as STM32F103C8s which officially only have 64KB flash. The additional flash isn't guaranteed so not a good idea to use in production. I do have some STM32F103C8s that only have 64KB flash and reading the flash size register also reports 64KB though so 128KB isn't guaranteed. Other manufacturers like Cypress do the same thing with their uCs but they hide the additional RAM/flash and it can't be used without some complicated tricks.

author: castingflame
author_rank: Regular Contributor
timestamp: March 27, 2019, 09:07:03 am
content: Interesting. Thanks tsman for the clarification but I still do not understand completely how 64K can just appear in the chip unless it is there by design and why it would or would not work unless it is not guaranteed because of poor yield for the second 64K.

author: tsman
author_rank: Frequent Contributor
timestamp: March 27, 2019, 09:36:31 am
content: It is a balance between making multiple designs with varying amounts of flash and making more of the larger part and sell it as the lesser part because it is cheaper or yields are better. In this case, ST would have been making STM32F103CBs which has 128KB flash and packaging them as STM32F103C8s which officially only have 64KB flash. The additional 64KB may be untested or it may be perfect but ST aren't going to guarantee it even if it perfect. Presumably ST made a new revision at some point with a die shrink or redesign which is why some 64KB parts do only contain 64KB.I wouldn't use the additional 64KB for production though. Always buy the proper part for production use. The price difference is tiny and just not worth the potential headache if that additional flash is actually marginal in some way.The GigaDevices GD32 clone of the STM32 has a separate flash die inside the chip they can swap out easily. It isn't integrated into a single die with the ARM core + peripherals like a STM32.

author: iMo
author_rank: Super Contributor
timestamp: March 27, 2019, 10:52:35 am
content: The most expensive part of the IC fabrication process today is the production of masks (usually a dozen or more per set) needed for the optical lithography. It may cost from hundreds to millions of USD per a single set of masks. And you need many sets, moreover, with any chip revision you need new sets.Therefore, for a manufacturer the costs of production of 64kB or 128kB chip is almost the same. The silicon foundries usually charge flat fee for a wafer, and even you may get more 64kB chips from a single wafer (because it is smaller) the cost of a set of masks does not justify to go with both 64kB and 128kB.

author: mac.6
author_rank: Regular Contributor
timestamp: March 29, 2019, 07:46:24 am
content: Last chip design I saw last year was 42 layers, so indeed 42 masks. Can't disclose the price but it was rather low per mask, but 42 adds up fast (90nm process, so old and cheap).

author: guenthert
author_rank: Frequent Contributor
timestamp: March 29, 2019, 05:22:57 pm
content: There seems to be some confusion.<quote>Many of us are aware of the STM32C103 boards referred to as the "Blue Pill".</quote>afaik, there is no STM32Cxxx and modules with the STM32F103C8 are referred to as Blue Bill. Probably just a typo, but perhaps indication of sloppy spread sheet reading.Said that, the batch of 5 (ordered, 6 shipped) I received had indeed a 10kOhm USB pull-up resistor, when you find all over the 'net that it ought to be 1.5kOhm. I fixed one, but still Arduino programming over USB doesn't work (regardless of pull-up resistor value), can't tell, if other USB functionality works. The units can be programmed using the ST-LINK/V2 interface, so they aren't complete duds. I put it aside and used a Teensy LC (considerably more expensive, but works as advertised) for now.I was wondering, whether the 10kOhm/1.5kOhm mismatch is a SNAFU at the factory which meant to discard the units, but they somehow made their way to Fleebay or whether there's some misunderstanding of the schematic and intended use.

author: martinayotte
author_rank: Regular Contributor
timestamp: March 29, 2019, 08:00:32 pm
content: Quote from: guenthert on March 29, 2019, 05:22:57 pmMost BluePills don't have any preloaded bootloader, so, you have to upload one using either STLink or Serial.Then, having a bootloader installed, you will be able to use DFU.

author: guenthert
author_rank: Frequent Contributor
timestamp: March 29, 2019, 11:32:26 pm
content: Quote from: martinayotte on March 29, 2019, 08:00:32 pmThanks, but I did that already (paying attention to getting therightbootloader -- in my case the one for those boards which have the LED on PC13). But there is of course the possibility that I screwed up somewhere in the process.

author: castingflame
author_rank: Regular Contributor
timestamp: March 30, 2019, 06:09:56 am
content: QuoteRoger Clarke does mention on the STM32duino Wiki or Github page that not all BluePills work with the bootloader, but I can not recall what the reason given was.I personally have also seen this issue. When I did have a working bootloader installed I used it for a few minutes then went back to serial & ST-Link. The bootloader takes at least twice as long to program the BluePill and it also take up some space. I use serial programming (need to hit reset) when I want some serial debug via the serial terminal and use ST-Link (no need to reset and is also faster) when I do not need serial terminal info.