Trying to source a STM32 stm32h757bit6 - Page 1
Forum section: electronics / general

author: MarkS
author_rank: Unknown
timestamp: December 24, 2022, 10:10:38 pm
content: I understand we're still feeling the effects of the chip shortage, but I cannot find this part. I did "find it" on Alibaba, but that immediately raised red flags for me. I would have no way to verify if it was genuine. And it's not just this particular model. I cannot find ANY STM32 microcontrollers! Zero in stock. Everywhere!I don't guess it has to be a STM32 part, but I need at least 100 GPIO, a memory controller and a USB 2.0 high speed bus.What are my options, other than sourcing a product that uses this chip (how would I even find that out?!) and scavenging it off the board? I even thought, "Screw it! This is the perfect excuse to get my feet wet with FPGAs!" 🤣🤣 Yeah... About that... 🤦‍♂️

author: MarkS
author_rank: Unknown
timestamp: December 24, 2022, 10:17:15 pm
content: ...

author: MarkS
author_rank: Unknown
timestamp: December 24, 2022, 10:18:33 pm
content: Oops... Quoted myself... 🤦‍♂️

author: martinribelotta
author_rank: Regular Contributor
timestamp: December 24, 2022, 10:38:15 pm
content: Sound like a work for an ice40hx1k or 4k in lqfp144 package...HX1K is in stock and fully provided (3k units at least)https://www.digikey.com/short/99f9dj9j

author: MarkS
author_rank: Unknown
timestamp: December 24, 2022, 10:51:51 pm
content: That's interesting, but I didn't see an exposed external memory interface or USB. Now, being an FPGA, I could just make that work, but this would be my first use of an FPGA, so I'd like as much exposed as possible. I was really interested in the XILINX Zynq line, but can't find them!

author: MK14
author_rank: Super Contributor
timestamp: December 25, 2022, 12:01:21 am
content: Does this meet your long list of requirements?https://www.mouser.co.uk/ProductDetail/STMicroelectronics/STM32L4S9AII6?qs=wd5RIQLrsJhTDo%252BO4Z5Vcw%3D%3DSTM32L4S9AII6Number of I/Os: 131 I/OFlexible static memory controller (FSMC)Stock:2,464 Can Dispatch ImmediatelyThey seem to have a number of other STM32's in stock as well.

author: luiHS
author_rank: Frequent Contributor
timestamp: December 25, 2022, 12:36:59 am
content: At the time, at the beginning of the crisis, when there were still stocks, I bought quite a few H747 and H757 (LQFP and BGA), but for only one reason, they are the only microcontrollers I know of that decode JPEG images by hardware, which makes it possible to make an MJPEG video player with MIPI screens. That's why I bought it and I have several projects in development with MIPI screens of various sizes and shapes.If you don't need to play videos, then there are other much cheaper options. I am working with the NXP i.MX RT series, specifically with the RT1064, although I also have RT1024 and some RT1172 and RT1176.Until very recently there were still RT1064s at Mouser, I bought the last ones, but now they won't be there until the middle of next year, you're late. But with the H747 and H757 it is worse because there is not even an expected date for availability.Right now there is still stock of the RT1024, it is a good microcontroller, Cortex M7 at 600Mhz with integrated flash. I think it's one of the few 32-bit Cortex M7s still in stock.Another piece of advice in times of crisis, like the current one. When you see that there are thousands of units of a BGA microcontroller in stock, check the pitch, surely they are very fine pitch, 0.65 or 0.50mm, very difficult to solder safely, that's why nobody wants them and there are thousands in stock.At BGA I only work with a minimum pitch of 0.8mm, most of them are out of stock at the moment. The RT1024 is LQFP144, it is a good choice as long as there are no BGAs, like the RT1064, in stock.

author: tellurium
author_rank: Frequent Contributor
timestamp: December 25, 2022, 12:54:46 am
content: Quote from: MK14 on December 25, 2022, 12:01:21 amOmg these things cost like a car

author: MK14
author_rank: Super Contributor
timestamp: December 25, 2022, 02:23:57 am
content: Quote from: luiHS on December 25, 2022, 12:36:59 amhttps://www.digikey.co.uk/en/products/detail/microchip-technology/ATSAME70Q19B-AN/9695802In stock at the moment (at least 3 different versions/types available), easier to solder 144-LQFP (20x20), cheaper, and M7 class, with the right peripherals as well, at a quick glance.But 300 MHz max clock frequency, I don't know enough about the requirements, to know if that is suitable.List:https://www.digikey.co.uk/en/products/filter/embedded/microcontrollers/685?s=N4IgjCBcoLQCxVAYygMwIYBsDOBTANCAG4B2aWehA9lANohwAcATCyALqEAOALlCCAC%2BhGM0QgUkHgCcArgRA1I9AKwdBGoA

author: MarkS
author_rank: Unknown
timestamp: December 25, 2022, 04:16:51 am
content: Thank you everyone for the replies. The L series will work. There are so many variants that I passed them up. It's like ST sticks a bunch of parameters into a random part generator and makes whatever it spits out! 😳 Maybe if they pared down their product lineup, they would be able to get some fabed... 🤔🤷‍♂️ I'd prefer the H series, but in truth, it's overkill.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: December 25, 2022, 09:41:31 am
content: ST is also known to just stamp different numbers on the same part.I've read many reports of their uC's having twice as much memory as the datasheet states, or USB still working on a part that should not have USB.Their marketing department either thinks they can sell more parts if they have more part numbers, or when some "cheaper" variant becomes popular, then can respin the die of such a part later to reduce silicon size and improve profit, and they just let the market decide which parts become popular enough to warrant a respin of the die.

author: MarkS
author_rank: Unknown
timestamp: December 25, 2022, 10:00:21 am
content: Quote from: MK14 on December 25, 2022, 12:01:21 amYes, it does, BUT... I doubt I'd get the part to work because of the package. I did find a similar variant on Digikey in a TQFP-144 package.Quote from: Doctorandus_P on December 25, 2022, 09:41:31 amAs a business strategy, that'll ensure you run the business into the ground! 😳🤦‍♂️ Makes me rethink my reluctance to buy the part from Alibaba. 🤔Quote from: tellurium on December 25, 2022, 12:54:46 amNot bad for a hobby project, but as LuiHS stated, it's a fine pitch BGA part. If the pros won't touch it for that reason, you bet I won't be using it!

author: MK14
author_rank: Super Contributor
timestamp: December 25, 2022, 03:05:55 pm
content: Quote from: MarkS on December 25, 2022, 10:00:21 amYou're right. I should have taken that into account.

author: MK14
author_rank: Super Contributor
timestamp: December 25, 2022, 03:10:26 pm
content: Quote from: Doctorandus_P on December 25, 2022, 09:41:31 amI've heard that masks have become extremely expensive these days (especially for the latest, smaller feature sizes, versions), so they want to minimise the number of masks they make. So I have a degree of sympathy with them. But, the marketing department, can be too eager, to create too many different parts, for sales reasons, rather than sound engineering wisdom.Also, although the part(s), may have extra bits, you don't know if those extra bits, such as memory, really work properly. I.e. Did they pass all the extensive manufacturer's tests, for the datasheet checks/compliance?E.g. It may have more flash memory, but perhaps it is faulty in some way, so could be problematic, and can't store data bits for long enough, etc. So it got rejected for use as the top flash memory sized part, but accepted, as a lower end chip, with less flash memory.

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 25, 2022, 07:54:13 pm
content: There are some NXP MCUs available at the moment in the RT10xx series that could be a match. Not necessarily available in the packages you want though, I dunno.STM32L4 series is great if you want something moderately powerful with very low power. I don't know what the OP meant by "memory controller" and "USB 2.0" though.If the memory controller should be able to accesss SDRAM, then forget about the L4 series (AFAIK). If it's async static RAM, then yes.As to USB, if by "USB 2.0" the OP meant USB HS (2.0 doesn't necessarily imply HS), then forget about the L4 series as well. For USB FS, then yes.

author: hans
author_rank: Super Contributor
timestamp: December 26, 2022, 09:01:43 am
content: Quote from: Doctorandus_P on December 25, 2022, 09:41:31 amI think I've heard these stories as well, but I was under the impression these occured with ST cloned parts (e.g. the popular STM32F103) that are branded ST. Some of these clones may not even have the FLASH on-chip and use a 2-die construction. I could see it viable for clone manufacturers that hide behind different branding to not really care about their QA as much and install a 128K FLASH die in a 64K part if that's all they could get that day on the Shenzhen market.Maybe ST has a similar construction as well with this 64K/128K hidden FLASH thing. I'm sure professional customers won't touch that hack for a 5ct savings vs potentially throwing out hundreds or thousands or "bad 64K" boards. But for hobbyists it's quite a neat trick to use, especially since double FLASH on 64K is a very nice upgrade.I did that try to see if other peripherals were available on other parts, e.g. see if ciphers were available on a STM32F723 vs F733. I don't think it did, I'm not even sure the peripheral clock enable bit stuck on. Maybe they have a fuse to set the F723 vs F733 ID, which negates any 1s written to the clk enable bitfield, locking out the clock and thus making that peripheral region unaddressable. Sounds fairly simple to implement (1 fuse and 1 AND gate). But honestly, for hidden FLASH regions, ST could use an AND gate on the MSB address line to force it low and lock it out as well.Maybe I should have a poke around, sounds interesting.Anyway on-topic. Is this hobby or professional at large quantity? My experience for hobby is to be opportunistic. I picked up a couple of STM32H725 parts a few months ago when the 176-QFP variant popped up on Mouser. They were 15EUR each (not cheap), but I'd figure if I don't pick up 5 now, they'd be gone soon. And that was true; out of ~200 stock, everything was sold out in 1 day with 1yr lead time.For professional maybe focus on different parts. I've been able to purchase some of the L4 parts consistently in the last month. Some other parts also are promised stock and could be pre-ordered I imagine. But note those L4s don't have USB HS, so maybe not fit all your requirements.

author: MT
author_rank: Super Contributor
timestamp: December 26, 2022, 05:48:45 pm
content: Quote from: Doctorandus_P on December 25, 2022, 09:41:31 amAny links to those reports?

author: MarkS
author_rank: Unknown
timestamp: December 26, 2022, 06:45:57 pm
content: Quote from: hans on December 26, 2022, 09:01:43 amIt's a hobby project. I'm about to begin cancer treatments and will be stuck at home resting for the next few months, so I want to dabble with something more advanced than what I've previously done to keep my mind active.I actually got a response from a distributor about the STM32H chip. I can order one from them for $105 + shipping. The shipping is quoted at $60/per KG! 😳 I'm waiting to see if that is prorated for less weight. Given the current supply chain issues, I'm willing to spend that on the chip. I can justify the chip price. $60 shipping? For one chip?! 🤨🧐 Not so much!

author: MarkS
author_rank: Unknown
timestamp: December 26, 2022, 06:50:03 pm
content: Quote from: SiliconWizard on December 25, 2022, 07:54:13 pmSorry about that. I was going off of the data sheet and wasn't clear. Yes, USB HS interface and external memory controller for interfacing with SRAM/DRAM/etc.

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 26, 2022, 07:03:51 pm
content: Quote from: MarkS on December 26, 2022, 06:50:03 pmSRAM and SDRAM are completely different beasts and require different controllers, so as I said don't expect the support of one to imply the support of the other, this is absolutely not the case in general.Usually, only the higher-performance MCUs (typically with a Cortex M7) have an SDRAM controller, and same for USB HS. It's relatively rare with Cortex-M4-based stuff. Certainly the STM32L4 series supports neither. The NXP RT series does.

author: tabemann
author_rank: Contributor
timestamp: December 26, 2022, 07:04:01 pm
content: Quote from: MT on December 26, 2022, 05:48:45 pmI second that the genuine STM32F103C8 is indeed well known for having 128K flash despite being marketed as having on 64K flash. Actually, one test for being a genuine ST part is checking for a working upper 64K of flash

author: MarkS
author_rank: Unknown
timestamp: December 26, 2022, 09:21:10 pm
content: Quote from: SiliconWizard on December 26, 2022, 07:03:51 pmUnderstood. I need at least 16 MB of external RAM. A low speed SRAM or high speed SDRAM interface is immaterial. I just need an external memory interface.

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 27, 2022, 03:19:10 am
content: Quote from: MarkS on December 26, 2022, 09:21:10 pmProblem with "SRAM" is that at 16MB it will be very expensive.Your alternative, if you don't need high bandwidth, is to focus on PSRAM. You can get relatively "cheap" PSRAM ICs with this kind of memory size. PSRAM usually has a QSPI interface, so all you need to use them is a MCU with support for QSPI. There again the NXP stuff has support for that, but a lot of other MCUs in various ranges so that opens a lot more possibilities while keeping cost low.PSRAM is internally just some type of SDRAM but with an integrated controller and a QSPI interface.