| ▲ | Playing with the STM32MP2(serd.es) |
| 34 points by dverlaeckt80 6 hours ago | 21 comments |
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| ▲ | throwaway81523 3 hours ago | parent | next [-] |
| Despite STM32 in the product name, this is a dual core Cortex-A35 SOC intended to run Linux, though he brings it up as bare metal. The STM32MP257F-EV1 dev board that he used costs $425 at Digikey. His thing is interfacing it to FPGA's. So this seems to be a hardware person's product. Most of us can probably use simpler stuff. The Pocketbeagle 2 looks interesting to me. |
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| ▲ | Neywiny 3 hours ago | parent | next [-] | | I think you mean "despite the STM32 in the product name, they're 64 bit compatible cores." Because STM8 was 8 bit (though I've never seen one in any design ever, I'm sure they're just before my time) and STM32 MCUs and MPUs were always 32-bit. I'm worried they dug too deep a trench with the 32. Like how do much from Espressif is an ESP32 now despite them ranging from slower single core to faster dual core, now even with mmu, some with Wi-Fi some not... What is in a name? | | |
| ▲ | throwaway81523 an hour ago | parent | next [-] | | STM32 processors have traditionally been M-series 32-bit ARM cores including M7. I don't know if there have been any exceptions before this. But A-series is application processors with MMU's, DRAM interfaces, etc. STM8 is still a thing and they were popular cheap embedded boards before ESP32 took over. They were ok as a cheap alternative to Arduino-compatible AVR boards. I have a few of the boards around. They were around $1 each on Aliexpress and have 8K of flash and 1K of ram, which is enough to run interactive Forth, and there's an SDCC compiler target for them. | |
| ▲ | ranger_danger 3 hours ago | parent | prev | next [-] | | Or they could have just meant STM32 is normally synonymous with "typical slow single-core MCU" compared to multi-ghz Cortex SoCs that we see in higher-end devices that run Linux? | | | |
| ▲ | hackingonempty 10 minutes ago | parent | prev [-] | | That's marketing. The iMac was a huge hit so Apple started releasing iEverything. Denny's had a hit with its "Grand Slam" breakfast now they have ten different "slams" on their menu, |
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| ▲ | kvemkon 2 hours ago | parent | prev [-] | | There is STM32MP257F-DK for $103 (without PCIe). > The Pocketbeagle 2 looks interesting to me. If only it had 2GB+ RAM. Since it has 4 cores, even more RAM would be better. And 1Gbit Ethernet is what I'm missing. |
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| ▲ | dlcarrier 2 hours ago | parent | prev | next [-] |
| From STMicro: STM32MP257 application processors (STM32 MPUs) are based on a dual Arm® Cortex®-A35 cores running at up to 1.5 GHz and Cortex®-M33 cores running at 400 MHz.
Why do they put a full-desktop-capable A35 processor in the sme product line as the M0 microcontrollers? I presume they're trying to milk value out of the name recognition but they're just diluting the name. |
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| ▲ | zwieback 2 hours ago | parent | next [-] | | The idea is to move realtime-ish stuff to a popular processor many people have worked with and moving the Linux stuff over to an appropriate platform. When it came out we used STM32MP257 to demo a quadrature encoder debugger/logger (for internal use, not a product) since the IO supports easy interfacing of encoders. The micro's peripherals (SPI, I2C, GPIO etc.) are easy to program at the register level and you can run a simple mainloop+interrupts thing on the micro, then run Linux for your UI, networking, etc. The fact that there's not much activity around these kinds of platforms (CPU+micro or CPU+FPGA) suggests it's too hard to combine the two in a way that makes sense for enough people, easier to just use standard components and have them side-by-side on the PCB. It is nice to have them on the same die, though, for people like myself who like to work on both ends but don't know how to make their own PCBs. | | |
| ▲ | ACCount39 an hour ago | parent [-] | | The truth is that those are just niche items. Having a need for both a Linux-grade CPU and a real time MCU-like core is not that common. It tends to show up in projects too advanced for most to attempt. | | |
| ▲ | azzentys an hour ago | parent [-] | | That's untrue. Almost all the products I worked with in my last company had such architecture - which we leveraged (this was Ag industry). It's very easy to work as they have shared memory to talk to each other. | | |
| ▲ | ACCount39 an hour ago | parent [-] | | That's at least a tier more advanced than mainstream. And if by "very easy to work" you mean "just allocate a shared memory block and put a mailbox in there for the Linux userspace and the RT MCU to talk to each other", you may have inflated expectations of what an average developer using an SBC can easily do. It's "very easy" in the same way rolling your own PCBs or writing your own drivers is very easy. Seasoned developers do it without thinking twice, and then stand dumbstruck when they see entry level developers avoid that like the plague. Not like we're lacking for the offerings. Plenty of modern SoCs have MCU-like real time cores in them - intended for low power operation, real time control, or both. Even the mainstream RPi 5 boards ship spare PIO and MCU cores - in the RP1 chip. The vendor just couldn't be bothered to document that. | | |
| ▲ | nateglims 25 minutes ago | parent [-] | | What do you mean by mainstream? There’s whole sectors of industrial and automotive using these AMP SoMs. And relative to these RPi only recently began providing options that you could design into an embedded product at all. Their FAE and supply presence is way behind. | | |
| ▲ | ACCount39 a few seconds ago | parent [-] | | By "mainstream" I mean "the bulk of development work done", not "the bulk of units shipped". The boards that people reach for when they roll their first projects, the hardware that ends up in early prototypes and one-off devices, the hardware that gets targeted by open source projects. The chips that return more than a "databrief" 8 pages long and a single page on a vendor site with "contact sales for more information", the boards you can actually buy with a fixed price tag and can find writeups on how to use them for specific things. If you know what "FAE" is, let alone can get into a meeting with one, you're deep in the trenches, and are pretty much expected to wrangle an extremely poorly documented MCU core that happens to be shipped in a SoC into submission. |
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| ▲ | dragontamer an hour ago | parent | prev [-] | | Seems normal to me. Microchip also puts their 32-bit and 64-bit chips with their SAM and PIC64 names. Must be an embedded thing. |
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| ▲ | ranger_danger 3 hours ago | parent | prev | next [-] |
| > And a lot of these parts either don’t have crypto acceleration or security-by-obscurity lock up the docs to the crypto accelerator, which is an absolute dealbreaker for me. I have to wonder if locking up the docs is some kind of export control or government contract requirement. |
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| ▲ | jauntywundrkind 2 hours ago | parent | prev [-] |
| I'm so glad we are finally seeing small cores, something to threaten the Cortex A7, which harkens back to 2011!! But also: Cortex A35 is from 2015! And it's still just a trickle of these small application processor cores. Having a MMU enables so much more. Look at what Baochip and Xous are doing, with small cores but with MMU, for radically better interesting OS / systems architectures. It just feels so cursed, is so beyond my surprise here well past half way through 202X that so many cores from early 201X are still not just alive but utterly dominant. Something has gone super super super wrong in the House of ARM! |
