Will Arduino use ultra low power Microchip SAM L10/SAM L11, .8mA active usage?

Will Arduino use ultra low power microcontrollers such as Microchip SAM L10/SAM L11 (.8mA active usage @32mhz)?

I'm trying to use 3.3V Arduino Pro Minis and the new Arduino Nano 33 IoT for a low power application where I can power it via a 3.5V, 4.5V, 5V, or 6V solar panel in cloudy conditions. Also it would be useful for later projects where long battery life would be nice to have.

I was attempting to do this without implementing any power saving techniques
i.e. (Gammon Forum : Electronics : Microprocessors : Power saving techniques for microprocessors

and without taking off the power led and voltage regulator.
This website has some good suggestions to do this:

After taking out the power led, the website suggested to switch out the
voltage regulator (Low Quiescent Current LDO):

I really wish the Arduino Team will look into using the Microchip family of processors.
The links below describe the features they have as well as the power usage specs.



I really wish the Arduino Team will look into using the Microchip family of processors.
The links below describe the features they have as well as the power usage specs.

32-bit Ultra-Low-Power and Low-Power MCUs | Microchip Technology

You realize that the SAMD21 processors used by many Arduino boards show up in the middle of that list, at about 2.25mA@32MHz?
None of the SAM-L chips have USB built in, which is problematic.

Before you start calling out for new products - are you sure you can't just, well, make use of power management techniques? On a bare '328p in SLEEP_MODE_POWER_DOWN, power consumption is negligible, and I'm wondering what you need to do that precludes sleeping for most of the time while on such a limited power budget.

I mean, if you need to communicate wirelessly, handling the surge of current associated with that will be your problem.

Low-Power Sleep Modes and Operating Voltage

Active mode current down to 25 μA/MHz
Deep sleep current down to 100 nA
SRAM retention (40 KB) down to ~1 μA
1.2 μs wake-up time from idle state
Fully operational down to 1.62V while still maintaining all functionality, including analog functions
Highest certified ULPMark™ score for any Arm Cortex-M23 or Arm Cortex- M0+ class device; SAM L11 MCU achieved ULPMark score of 410


These are the specs for the 32 bit Microchip processors.
It seems their deep sleep mode is better than the 328P no?
I would love to use the chips at 1.62 volts with i.e. 2 AA batteries and the use of analog functions is a requirement for one of my projects.

I just got an Arduino Nano 33 IoT.
I know it comes with a couple of sensors, but I can't find specs on it regarding
deep sleep mode current consumption, etc.
I don't know the details of how much current consumption is regarding the built in USB and it would be nice to have it on the SAML10/11, but I'm getting by with a usb to serial converter on the Arduino Pro Mini.

Even without the power regulator and the power led on the Arduino Pro Mini, the lowest deep sleep mode with watch dog timer enabled is .0045 mA or 4500 nA based on the site below:

In terms of regular/idle/deep sleep mode aren't the Microchip processors a better option in terms of power usage?
Wireless application or not, if a battery were used wouldn't it last longer for a project application?
I've seen battery applications for various things online like weather stations, farming, long distance intermittent signal transmission, etc...

To put things into perspective I was expecting an option to keep the power led off on the Nano 33 IoT or even on the Nano Every in active mode. Can this be done while they are not in deep sleep?
I was powering the Nano 33 IoT via a 5V 100 mA solar panel and it was able to stay on with full sunlight, but I'm trying to power it with i.e. cloudy sunlight or morning sunlight. It either couldn't stay on, or the power led was barely flickering at times in such weather conditions. I used such a small panel for portability and small foot print reasons.

I don't have much experience with the the low power modes of the 328P but I've been trying to find a way to use the 3.3v Arduino Pro Mini at a lower voltage and clock frequency. With my current application I'm using 2 analog inputs and smoothing them 64 times.

These are the specs for the 32 bit Microchip processors.
It seems their deep sleep mode is better than the 328P no?

Maybe. Low power specifications can be difficult to actually achieve in practice, and it can be pointless to chase "better" if an easier solution is "good enough." You've already noticed that for current CPU chips, "board level" design issues are more of a power hog than the CPU itself. You need to seek out (or design) a better board, rather than chase a new CPU that will involve a lot of software work (and the SAML10 is a different ARM Core than the SAMD chips.)
(It would be nice to have a board and "core software" specifically aimed at low-power. I don't know of any, offhand.)

I agree about the board designs.
My main purpose is to be able to use a microcontroller without putting it to sleep using really low amounts of power.

i.e. cloudy weather solar panel powered Arduinos using low voltage <3.3 volts.

I read on the forum and elsewhere that converting via buck converter, etc.. from higher to lower voltages results in inefficiency losses. So I got a 3.5v solar panel and am using a buck converter to input 3.3 volts into the microprocessor.
I'm currently powering an ESP32-Pico-D4 Mini development board with this.
See screen shot below.

(:wink: 7 nm Arduinos in 2020?)

I've seen a couple of boards out there that emphasize low power usage, but I think they are relatively pricy compared to the ~$2 clones of the Arduino Pro Minis I get online. Hopefully they will get lower in price once more people buy them:

Microchip does have an IDE with examples, although I can't find that CPU specifically on the cloud based IDE. All the options available are for the PIC series.
(interesting thing, I didn't know Microchip bought Atmel in 2016)

There are three main boards I'm trying to use for projects right now:

  1. Arduino pro mini with nRF24L01+
  2. ESP 32 Pico D4 mini development board (bluetooth and Wifi in one small package)
  3. Arduino nano integrated with nRF24L01+

Regarding wireless transmission of data that someone mentioned below,
ESP-Now protocol seems to be best power saving method that I found based on the little bit of research I've done. The Arduino pro mini with nRF24L01+ also seems to be a good option and it may be using less power than the ESP32.


I took a look at your Tindie store, do you have any power consumption specs on your boards?

I really want to avoid all these steps recommended on these sites:

Do you have any board that runs at 1.8V and no power led or ability to turn them off?

For my current application,

  1. I have 2 analog inputs (12 bit ADC) coming in from 4 photodiodes (2 pairs that are in series)
  2. Will have MPU-6050 sensor to determine tilt angle
  3. I will transmit the values (2 analog inputs, 1 I2C bus value) wirelessly periodically.
    In the beginning of the cycle they would have to be sent probably every 10 seconds.
    After a minute or two they can be sent every 4 minutes or so.

Picture below of application,
ESP32-pico-d4 when it's powered via a 3.5V solar panel and buck converter

Any thoughts on using this for your boards?
After taking out the power led, the website suggested to switch out the
voltage regulator (Low Quiescent Current LDO):

Using development boards like the Nanos, ESP based etc. will never give you optimum power consumption because these contain all sorts of power hungry clutter to simply development.

Low Power design starts with the architecture of your application, which I guess in your case is some sort of solar tracking device, and the techniques are common which ever MPU chip you use. Things like not wasting power with linear voltage regulators, omitting power hungry peripherals, switching peripherals off when not in use and minimizing on time, lowering clock speed to permit lower voltage use, using sleep modes etc. etc. For solar powered devices, you also have to look at power management, battery charging etc.

Anyway, this application appears not to have any special requirements, although the 12 bit ADC resolution you have mentioned , if it actually required, would rule out ATmega328p based systems unless you add an external ADC. However, I’d start on the basis of a bare bones ATmega328p unless a requirement emerges which forces the use of a more capable device.

I'm trying to avoid using a battery for the solar powered Arduino.
Basically I want it powered on from sunrise to sunset.
It's for a solar tracker.
That's my reasoning for why we should have an ultra low power consumption development board from Arduino. It's why I got the Nano 33 IoT, but will have to wait and see how to program it properly before I can reap any potential power saving benefits from the new processor.

The wireless part is necessary because my wires kept getting caught in my rotating structure.
The ESP-Now protocol seemed to be the best low power option for wireless data transmittal vs bluetooth, wifi, and RF. (Unique MAC addresses used, this will prevent interference of pairs of devices)
The nRF2401 is another alternative (using a 5 byte address I believe will also prevent such interferences from happening between matching transmitter/receiver pairs).

The 12 bit ADC isn't necessary, it's just what comes by default with the ESP32.
I thought it would be nicer to have for sesparating light shadows for the solar tracker, resolutions, and accuracy but other future applications as well.

Right now I am actually not using the linear voltage regulator of all the devices.
I'm using one or the other of these step down buck converters and inputting voltage into the 3v3 pin or Vcc pin:



In this case what is the best thing to use to regulate voltage coming in from for example
i.e. 2 NiMh Batteries @1.2V (2.4V) or a 3.5V solar panel (in cloudy weather this voltage may be 1 volt lower, etc)?

Let's say I plan on running the 328P at 1 mhz and 1.8V, then 2.4V batteries or a 3V solar panel should suffice I think.

I haven't found any panels selling that are rated at 1.8 volts yet.
Although I will look for slightly higher voltage to compensate for the cloudy/sunrise weather.

Although I've been thinking of getting some part modules of larger SunPower solar panels with
(21% efficiency) and seeing if they will deliver better results in cloudy weather.

An ATmega328p @ 4Mhz can run at any voltage between 1.8 and 5.5 volts.
If you are using only a solar panel and not attempting to store the surplus energy in batteries, you can simply use a zener diode or any converter to lose anything in excess of 5.5 volts so the panel voltage is not critical.

Using the solar panel to charge batteries (using an appropriate step up / step down converter) and simultaneously powering the MPU from those batteries could have the advantage that a passing cloud would not cause the system to stop.

You can get rotating contacts (slip rings) example: https://www.bc-robotics.com/shop/slip-ring-3-wire-10a/ which could solve your tangled wire problem as an alternative to the various radio based solutions.

Where on the ATmega328P sheet does it say that it can run off of 1.8V?
I couldn't find it.

I'm thinking if Arduino supports the SAMD21G18A which is in the Nano 33 IoT then will it have better low power characteristics since it's a newer generation of processors???
I wonder how much current it would consume at lower mhz rates.


Pg. 986 and onward describes power consumption characteristics.

DDIN = 1.8V, CPU is running on Flash with three wait states

Not sure what 3 wait states means.

@1.8V highest current consumption I can find is 4.7 mA
What determines the max clock frequency I need for a project?
i.e. in my example:
2 analog inputs sampled 64 times to smooth out readings
1 MPU6050 elevation angle reading of structure
wireless transmittal of results either via
or future Nano33 IoT data transfer protocol

Regarding the passing cloud situation,
I've seen some chargers that are optimized for solar charging such as this:

However, I think NiMH batteries have a longer life vs Lipo batteries and have yet to find a similar charger for them. i.e. 2xAA NiMH (2.4V) at full charge.
I wish there was some cheap ultra capacitor or cheaper energy storage alternative.

Thanks for the slip ring idea.
I've used them in industry before.
Although on the elevation axis of the solar tracker it will not solve the wire traveling issue.

I'd rather stick to the wireless solution as it involves fewer parts and its cost would be lower.

Where on the ATmega328P sheet does it say that it can run off of 1.8V?
I couldn’t find it.
. . .

Microchip have got themselves into a complete mess with their ATMega328p data sheets. The one you have found is their “Automotive” chip version (but clear only from the URL). In principle, when a product is released, it is a very bad time to start fiddling around with the specification and issuing a whole load of specifications with contradictory operating parameters.

Here is another version , also from the Microchip web site, which quotes an operating voltage between 1.8 and 5.5 volts. See page 2. http://ww1.microchip.com/downloads/en/DeviceDoc/ATmega48A-PA-88A-PA-168A-PA-328-P-DS-DS40002061A.pdf

The other issues you want to discuss probably belong more in the project guidance sub forum. You’ll get best results when you focus on one topic per thread. Handled right, you’ll engender a lively discussion and the project is certainly interesting.

I see. Thanks for the correct sheet.

I agree will definitely discuss other portions of the project elsewhere, it can get confusing with multiple topics being added on to the main topic.

I hope others will find it useful to power their projects without batteries and
hopefully the ultra low power usage at i.e. 1.8V can be applied to many applications.
It would be nice if a development board from Arduino came out using lower power and voltage out of the box.

I attached the 3.5V solar panel and partially shaded it to see if the Arduino 328P can work.
I'm using the BlinkWithoutDelay example. It worked! (Powered it via Raw voltage pin)

If the SAMD21G18A which is in the Nano 33 IoT can run

@1.8V, highest current consumption I can find is 5.2 mA, CPU running a CoreMark algorithm

then things seem even more promising.

without putting it to sleep using really low amounts of power.

I guess. You do realize that you're going against several decades of low-power-design wisdom, by wanting to run continuously...

You might also want to look at some of the TI MSP430 products. They were low-power kings (at least at one time), some of them have enhanced ADC capabilities, and they can run a lot of Arduino code via "Energia"...

I have certain usage cases where I am using an Arduino Pro Mini almost like a PLC and in a production environment. I can't have it sleep in this case. Power supply in this case is not an issue.

Imagine though if a solar panel indoors during night time can power a soap dispenser application with a 20 watt led light bulb shining 2-3 meters above it as a power source.
I have several use cases/ideas where I want to do this but not enough power to power the Arduino with current size of panel below.

Sure smaller panels are good enough to power calculators indoor, but imagine the possibilities of all the other battery free indoor applications they can be used for.

Was there a specific reason for posting this 'tip' in 8 seperate forums ?