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Does the radio module stays active during watchdog.sleep() ?
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Does the radio module stays active during watchdog.sleep() ?

by raghavrathi on Fri Jul 01, 2022 11:07 am

Hi, I am using a Adafruit Feather M0 RFM95 LoRa Radio and I am trying to put the receiver to sleep. I was suggested to use watchdog.sleep(). Is it possible that the radio module keeps listening during watchdog.sleep()?
I am doing some experiments in which I am transmitting some LoRa trace with certain intervals, and I am making the feather go to sleep a little before the transmission on the signal, but some how the feather is still able to receive the messages.
Any help is appreciated.

Thank you.

raghavrathi
 
Posts: 13
Joined: Wed Apr 20, 2022 2:12 pm

Re: Does the radio module stays active during watchdog.sleep

by mikeysklar on Fri Jul 01, 2022 4:44 pm

Did you try:

Code: Select all | TOGGLE FULL SIZE
radio.sleep();
Watchdog.sleep(1000);


this is from the 32u4 LoRA guide:

https://learn.adafruit.com/adafruit-fea ... aw-2915777

To put the chip into ultra-low-power mode. Note that USB will disconnect so do this after you have done all your debugging!

feather_lora32u4supersleep_closeup.png
During the super sleepy mode you're using only 300uA (0.3mA)!

While its not easy to get the exact numbers for all of what comprise the 300uA there are a few quiescent current items on the Feather 32u4:

2 x 100K resistors for VBAT measurement = 25uA
AP2112K 3.3V regulator = 55uA
MCP73871 batt charger = up to 100uA even when no battery is connected
The rest is probably the Atmega32u4 peripherals including the brown-out detect and bandgap circuitry, ceramic oscillator, etc. According to the datasheet, with the watchdog and BrownOutDetect enabled, the lowest possible current is ~30uA (at 5V which is what we're testing at)

mikeysklar
 
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Re: Does the radio module stays active during watchdog.sleep

by raghavrathi on Fri Jul 01, 2022 5:00 pm

Hi Mikey,

No, I haven't tried radio.sleep(). Is it by LowPowerLab?
Can you please suggest me what library it is from?

raghavrathi
 
Posts: 13
Joined: Wed Apr 20, 2022 2:12 pm

Re: Does the radio module stays active during watchdog.sleep

by mikeysklar on Fri Jul 01, 2022 6:52 pm

Here are the details for radio.sleep() usage in our guide for the M0.

https://learn.adafruit.com/adafruit-fea ... aw-2060180

You can get radio.sleep() to work with the LowPowerLab's or the recommended Adafruit Radiohead fork.

https://learn.adafruit.com/adafruit-fea ... es-2328977

mikeysklar
 
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Re: Does the radio module stays active during watchdog.sleep

by raghavrathi on Sun Jul 03, 2022 9:53 am

Thank you, I will try it.

raghavrathi
 
Posts: 13
Joined: Wed Apr 20, 2022 2:12 pm

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