STM32H7 Dual core - power consumption M4 vs M7

> Same consumption for a ratio of two in frequency.

And probably a ratio of approximately 4 of data processing, because Cortex-M7 is dual-issue.

> For me, the power consumption is the main factor for choosing a processor (to make battery-powered data loggers)

What amount of data at what speed you have to process, that you are looking at such a powerful MCUs? Why not choose something from the L or G series?

> And probably a ratio of approximately 4 of data processing, because Cortex-M7 is dual-issue.

Ok, so on an application with data acquisition (i2s/spi/sai,...) and some burst to save data on memory( SD), it could be a better solution to go on M7 ?

(It seem that batch acquisition mode is here for that ?)

> What amount of data at what speed you have to process,

It can be ~3MB/s (up to 2 terabytes on SD cards). Or sometimes, non-stop acquisition during several years at lower speed (~4kB/s).

I know that the need of performance is far between these two functionality, and I could change my MCU according to the usage, but it implies more development, more costs, ... If I can find something versatile that can adapt in most of the situations, it could be great.

> that you are looking at such a powerful MCUs? Why not choose something from the L or G series?

I first looked into F4 series (with Ethernet for data retrieving, and I plan to use HS-USB), but once here, i saw that on that dual-core processor, they can be separately powered or not by user. So why should I go on one core M4 if dual core M7/M4 can do the same, with same power-consumption, or eventually better with more performance ? (and the price per unit is absolutely not a problem for me).

Thank you for your answer, I am a bit lost in this jungle of MCUs.

Programming for dual-core adds quite a bit of overhead. It takes longer to develop. The H7 series is not made for power efficiency.

Unless you actually need the 480MHz clock, or the dual-core functionality, I'd strongly recommend the L4 (or L4+) or similar series. You don't need either of these to log at 3MB/s.

> Programming for dual-core adds quite a bit of overhead.

That is, actually, the main reason too why I would not go on this family. But I would to be sure, it looks having great functionalities.

The L4 series, like the G4 lack of high speed connectivity. I need low power consumption for long time acquisition, but the maximum speed for data retrieving, that's why I consider going at least on F4 series.

(downloading hundreds gigabytes of data to a computer is already a pain with a (slow) 100MB Ethernet, that's why I don't want something too slow).

So, on F4 series (with Ethernet), power consumption is near twice better than the M4 on H7 series

(@90MHz 20mA / 43mA (periph enabled).

So, indeed, the H7 series may be a bit too much for my usage, but I still don't really understand what is the benefit of having a dual core with different families, the possibility to use one or the other independently, but with poor power performances on M4 core ?

The 34,5/35 mA with peripherals disabled for M7/M4 at 200/100 MHz rises a suspicion on measurement correctness. When measuring one core, did they put the other core in sleep mode or was it busy looping in hard fault handler?