EC21-E quecopen GPIO4 pin level in OFF state

Technical Subjects Open Solution
1

Hi,
In our product an EC21-E (quecopen version) is connected to an external MCU (STM8L151G2). In particular we have a connection between MCU and EC21-E GPIO4 (pin4) used as wakeup pin.

In a particular mode of operation, EC21-E is turned OFF, while MCU is still working and the pin which drives GPIO4 could have HIGH level (2V).
In this situation I can see an increase of consumption (about 13mA from a 4V supply voltage). As soon as the pin is driven LOW the consumption disappear.

So my question is: how is the status of GPIO in EC21-E during OFF state? I expect to be “floating” or is it necessary to “decouple” GPIO from external MCU?

Thank you

2

hi,davdav:
GPIO can define 8 states. The states defined when your MCU or peripherals use GPIO are power off states.
image

3

Hello @herbert.pan-Q,

Thanks for reply.

I modified my schematics in order to separate GPIO4 from MCU when EC21 module is OFF.

Regards