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STM32 MCU family goes 64-bit with the STM32MP2x (Cortex-A35)

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Re: STM32 MCU family goes 64-bit with the STM32MP2x (Cortex-A35)

#31

Post by eqvinox »

dragontamer wrote: post #22
gaudat wrote: post #16

Earlier quoted context omitted.

And the line between the two is blurred now with MCU running at hundreds of MHz. The STM32H7 is has more IPC than the original Raspberry Pi.

Do you take external DDR RAM on an application-class ARM core? You're an MPU. There's a blurry line sometimes, but Application-class (Cortex A* cores, like A5, A35, etc. etc.) are solidly MPU. Not even close.

> Do you take external DDR RAM on an application-class ARM core? You're an MPU.

The actual difference IMHO is the existence of an MMU. (Which is, fdpic/linux-nommu efforts notwithstanding, the general "Linux" condition.)

(Ex.: the SOPHGO SG2000 RISC-V chip comes with integrated DDR3 RAM, but is still solidly an MPU. I believe there are some ARM Cortex-A with integrated RAM too, can't think of any off the top of my head. [Ed.: nevermind, the SG2000 is dual RISC-V/ARM])

Re: STM32 MCU family goes 64-bit with the STM32MP2x (Cortex-A35)

#32

Post by eqvinox »

demondemidi wrote: post #20

10 year lifetime at -40 to 125C Tj is remarkable. Modern desktop CPUs are klutzes by comparison.

FWIW, at least 10 years (maybe at 85°C) is expected of any µP/µC worth its salt outside consumer use. It's just that consumers have accepted somewhat junk-y electronics as a fact of life. (Ok, the improvement cycle is also still quite rapid, meaning a consumer might want to update after 3~5 years anyway.)

Considering warranty periods on some goods, you also really don't want to build stuff with lower rated chips—it'll come back to bite you. Imagine having to pay a professional to swap out the controller board on a smart heating system… people might have accepted swapping out their TV every few years, but for a stove or fridge we're not there yet (and honestly I hope we never get there.)

Leaving the consumer space, it's just expected. If your CNC mill has an x86 control PC, it's a ruggedized industrial build, and those use embedded CPUs with better ratings. Cars are off on a different planet for regulatory reasons, same for aviation or military use.

Re: STM32 MCU family goes 64-bit with the STM32MP2x (Cortex-A35)

#34

Post by demondemidi »

eqvinox wrote: post #32
demondemidi wrote: post #20

10 year lifetime at -40 to 125C Tj is remarkable. Modern desktop CPUs are klutzes by comparison.

FWIW, at least 10 years (maybe at 85°C) is expected of any µP/µC worth its salt outside consumer use. It's just that consumers have accepted somewhat junk-y electronics as a fact of life. (Ok, the improvement cycle is also still quite rapid, meaning a consumer might want to update after 3~5 years anyway.) Considering warranty periods on some goods, you also really don't want to build stuff with lower rated chips—it'l…

I worked on validation at Intel and the primary source of faults over time is electromigration in the lower metal layers and our failure rates went out to 7 years (and there are multiple scenario %-failure curves in that window), and we dialed that back during the war with Athlon. Other sources of error are bit failures in sense amps in low-voltage SRAM circuits. Hitting reliability above 105 C Tj was really really really expensive for the big die sizes of Intel CPUs in the 2000s. Claiming the crown for low-yield high-performance CPUs required relaxing a lot of failure rates. However, intel was so paranoid to begin with, it didn't lead to massive failures but remember that industrial consumers have much more rigid requirements around reliability than gamers.

Re: STM32 MCU family goes 64-bit with the STM32MP2x (Cortex-A35)

#35

Post by Avamander »

FirmwareBurner wrote: post #2

Still calling your new 64-bit chips STM32, just like your 32-bit chips, instead of STM64, feels like your branding/marketing team is asleep at the wheel or just non-existent. Even Nintendo figured that out ~30 years ago.

It's like when Microchip bought Atmel they released the XTiny series. And they're not even that similar, so it has caused just a bunch of confusion. I suspect the same will happen with the STM32s that kinda are but also aren't.

Re: STM32 MCU family goes 64-bit with the STM32MP2x (Cortex-A35)

#36

Post by m-ee »

dljsjr wrote: post #26
demondemidi wrote: post #19

Earlier quoted context omitted.

What’s the diff between an SoC and MPU? Lack of a wireless connectivity subsystem?

MPU -> Microprocessor. MPUs typically have features that let it support a "full" OS; MMUs, speculative execution, advanced CPU pipelining features, etc. They also have a much higher RAM capacity. Often has more complicated power requirements when doing board design due to needing different voltage busses for different peripherals. Usually can't be run standalone, you have to bring some of your own peripheral hardware…

I tend to think of an SoC as "MCU with other peripherals not typically on an MCU", so BLE/WiFi radio or maybe gate drivers for motor control. But usually radios. As you pointed out "not typically on an MCU" is a moving target. Was a point where RAM and a decent ADC would be things you had to add externally.

Re: STM32 MCU family goes 64-bit with the STM32MP2x (Cortex-A35)

#37

Post by not_your_vase »

FirmwareBurner wrote: post #2

Still calling your new 64-bit chips STM32, just like your 32-bit chips, instead of STM64, feels like your branding/marketing team is asleep at the wheel or just non-existent. Even Nintendo figured that out ~30 years ago.

What's even more strange is that they have no problem marketing their 8-bit MCUs as STM8

Re: STM32 MCU family goes 64-bit with the STM32MP2x (Cortex-A35)

#39

Post by bpye »

eqvinox wrote: post #31
dragontamer wrote: post #22

Earlier quoted context omitted.

Do you take external DDR RAM on an application-class ARM core? You're an MPU. There's a blurry line sometimes, but Application-class (Cortex A* cores, like A5, A35, etc. etc.) are solidly MPU. Not even close.

> Do you take external DDR RAM on an application-class ARM core? You're an MPU. The actual difference IMHO is the existence of an MMU. (Which is, fdpic/linux-nommu efforts notwithstanding, the general "Linux" condition.) (Ex.: the SOPHGO SG2000 RISC-V chip comes with integrated DDR3 RAM, but is still solidly an MPU. I believe there are some ARM Cortex-A with integrated RAM too, can't think of any off the top of my he…

Nuvoton have some ARM9 parts with integrated DRAM for example [0].

It’s a little outdated but this blog post is a pretty good overview of the options available [1].

[0] - https://www.nuvoton.com/products/microprocessors/arm9-mpus/

[1] - https://jaycarlson.net/embedded-linux/

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