How to set the Pin mode for machine.deepsleep?

[robert-hh]

@KenM My best experience with going to sleep is by setting pins, which drive external loads, to input mode before going to deep_sleep. Then it is guaranteed to be in high impedance state. Unless of course you need it to drive something, which of course then consumes power.

[KenM]

@robert-hh
Changed the code to

from machine import Pin
RelayPin=Pin('P20', mode=Pin.IN)

Didn't change it, well, P20 is always draining current now, not only in machine.sleep and machine.deepsleep.

[robert-hh]

@KenM In that case you most probably have an problem in the circuitry. Do you have the choice to connect the LED to GND instead of 3.3v. I'm suspecting a current through the ESD protection diodes, when during deepsleep the I/O circuitry is switched off. Whether that works for you final set-up, is another story.

[KenM]

@robert-hh
I can change the board to source it instead of drain it but I was hoping this could be fixed in software, my I2C pins with external pull-ups don't draw current.
As test I tried to init P20 as part of the I2C but that didn't change the behavior of P20. (same for P19)

[robert-hh]

@KenM Cyn you tell which direction is the current flow of P20 is?

[KenM]

@robert-hh
It's sinking to ground through the external led/diode from 3.3V so there is only one direction possible.

[robert-hh]

@KenM I made a test myself, using a 1k resistor between 3.3V and P20:

• after boot: 78µA
• When set to OUT, value=1: 5.2 µA
• when set to OUT, value = 0: 3.2 mA
• When set to IN: 0 µA

In any IN/OUT/value setting: Current during deepsleep: 0 µA.
I tested also P10. Same behavior.
So there may be some other reason.

[KenM]

@robert-hh
That good news and bad news
You used this code above with the same firmware version like mine on a lopy4 on an extension board?

[robert-hh]

@KenM I use 1.20.1r1, but a homebrew extension board, with absolute no connection to P20 or P10, unless I wire some.

[KenM]

@robert-hh
I did cut the connection of P20 to the expansion board but kept the connection of P20 to my board, and it work perfect now :)

I will need to check if I lost some functionality of the expansion board.

All wasted time, because pycom refuses to give the schematic of the expansion board...

Thanks for doing some compare tests.

[jcaron]

@KenM Welcome to the pin cutters club (https://forum.pycom.io/topic/1673/pysense-pinout-wake-on-pin/19) :-/