Power consumption Explorer board ? Can't get it under 800uA

Are there users who can make the Explorer board into sleep with a very low power consumption ?
I can get the Lora module to sleep correcty, I see the current decrease with about 3mA (== RN consumption ) ( sys sleep command after a reset, wait a while after the sys sleep command )

I disable the USB of the uP with USB->DEVICE.CTRLA.reg &= ~USB_CTRLA_ENABLE;
I set the uP to deep sleep mode with SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
And I set the processor to sleep with __WFI();

Watchdog timer is set and active, though this doesn’t seem to draw a lot.
But the Bluetooth module of the Explorer, this bothers me a bit, I pull the reset line of Bluetooth low to let the module inactive. ( Have already tried it with SW command ‘Shutdown’, and making the Wakup pin High ( used the Sodaq Library of course )

Lowest amount of current stays around 800uA, as 50uA would be possible ??
I have a latest model Explorer, so also with the RN2483A version Lora module; the power consumption bug in this version should be solved if I’m correct ?

Is there another chip on the board I must command to sleep perhaps ?

PS I do measure current when powering the module through the on-board battery.
Does the MCP1711 regulator draw this much current perhaps ?? It shouldn’t be doing it I suppose.

So with this I’m curious if there are any other Explorer users who want to let their board deep sleep with a very low power consumption.

Regards, Arian.

To put the Bluetooth module in standby, you need to set BLUETOOTH_WAKE to OUTPUT, HIGH.

The SST25PF040C might take up to 50uAs (more likely around 10uAs) unless you specifically send the commands to put it into the low power mode.

The ATECC508A should sleep power is <150uAs, however, I’m not sure how to put that module in sleep mode (it might be automatic).

Hi Gabriel,

Thank you for your reply.
Current consumption went down to around 600 uA, by setting the Bluetooth Wake to high, this is a bit lower as before. I will test to set the SST25PF040 into low power mode, see if it makes a difference.
About the ATECC508, are there already usable libraries for this component ? Don’t like to reïnvent the wheel :wink:

Thanks, Arian.

I’m not sure if there is a library for the ATECC508A yet. I don’t believe Atmel has publicly released the full documentation for this module yet.

According to the datasheet though, if the two i2c lines are pulled low, the module will be put into sleep mode (see p.8). However, the i2c lines have pull-up resistors attached (as is normally required). There is also the possibility that the module automatically enters sleep mode after no more than 1.7s (see p.5).


For now I will take my luck that the ATECC goes to sleep by itself, though I will see if I can find out if I can command it to sleep. Taking down the SDA/SCL also results in letting curent flow through the 2 2k pullup resistors, which doesn’t help that much in being energy efficient :wink:
I guess the ATECC devices aren’t personilized yet ? or do they already have keys in them ?

There is library for the atecc108 to which the atecc508a is downwards compatible

There is indeed no full datasheet without an NDA for the 508a or 108a. If you are interested in the structure, the one for sha204a is available which uses the same library. So just different commands and op codes

For personalization you might want to use


Thanks Mario, I will study the EClet driver, which probably learns me a few things. Didn’t know EClet yet, only the Arduino lib from cryptotronix.


I just went through the summary data sheet again and thought I might give an update here, as there seems to have been a little mixup

Different then stated here before, the sleep current is listed as max. 2uA. What you might have meant is the sleep current under the conditions that,

When device is in sleep mode, V_CC <=3.6V, V_SDA and V_SCL < 0.4V

There the sleep current is at typ: 50nA max: 150nA (instead of uA)

Also, the device definitely goes to sleep through the mentioned watchdog though. Without the correct wake signal the chip stays quite as I can say from experience.

I’m trying to do the same but my results are not as good as yours…
@akonings would you mind to share your code?