8 ms·

Just from a glance at the microcontroller datasheets, it looks like the RA4M1's current draw in "Software Standby" mode is much lower than the older ATmega328P'

Just from a glance at the microcontroller datasheets, it looks like the RA4M1's current draw in "Software Standby" mode is much lower than the older ATmega328P's "power down" mode (5μA vs. ~50μA). But IIRC, the voltage regulators in previous Arduino boards already waste orders of magnitude more current than that, even while quiescent, making them not very suitable for battery-powered applications. So it remains to be seen if the R4 board improves on this.

sho_hn 4y ago
One thing that's makes the product line a bit hard to reason about is that they have a Wifi and a non-Wifi version using two very different MCUs with very different power use characteristics. I.e. even if you have Wifi disabled on the Wifi version, it'll behave very differently from the non-Wifi board. People looking up numbers or experiences will have a harder time. Add to this that afaict, the Arduino framework API currently doesn't provide fantastic abstractions for power/state management either. I had an Arduino-based esp32 project once and extracting best deep sleep performance definitely required reaching lower into ESP-IDF API instead (e.g. the difference between ext0 and ext1 wakeups and being able to shut off RTC memory in one but not the other). That means with the current framework, you have to potentially write non-portable code between two different versions of the "same Uno R4" if you want to optimize for low power. All of embedded is like this, really - scanning through and understanding a product line is basically a required skill - but meh, what a mess for beginners.
- nfriedly 4y ago
  I could be wrong, but my reading of the post was that the Wi-Fi version has two MCUs - the main RA4M1, and the S3 WiFi module. So, if you turn off wi-fi, they should be effectively the same board.
wombat_trouble 4y ago
I'd wager that 99% of Arduino enthusiasts (and a good percentage of industrial hw engineers...) do not have a habit of using power save modes on bare metal.

sho_hn 4y ago

One thing that's makes the product line a bit hard to reason about is that they have a Wifi and a non-Wifi version using two very different MCUs with very different power use characteristics. I.e. even if you have Wifi disabled on the Wifi version, it'll behave very differently from the non-Wifi board. People looking up numbers or experiences will have a harder time. Add to this that afaict, the Arduino framework API currently doesn't provide fantastic abstractions for power/state management either. I had an Arduino-based esp32 project once and extracting best deep sleep performance definitely required reaching lower into ESP-IDF API instead (e.g. the difference between ext0 and ext1 wakeups and being able to shut off RTC memory in one but not the other). That means with the current framework, you have to potentially write non-portable code between two different versions of the "same Uno R4" if you want to optimize for low power. All of embedded is like this, really - scanning through and understanding a product line is basically a required skill - but meh, what a mess for beginners.

nfriedly 4y ago
I could be wrong, but my reading of the post was that the Wi-Fi version has two MCUs - the main RA4M1, and the S3 WiFi module. So, if you turn off wi-fi, they should be effectively the same board.

wombat_trouble 4y ago

I'd wager that 99% of Arduino enthusiasts (and a good percentage of industrial hw engineers...) do not have a habit of using power save modes on bare metal.