LPC55S69 : restore GPIO configiration

[EugeneHiihtaja]

Hello !

Looks like GPIO peripherals is completely lost during PowerDown mode and we should backup and restore

some registers from it by software

I can see DIR registers for port 0/l is reconfigured as inputs ( set to 0).

And I can read and write it back after exit from PowerDown mode.

 But what about other registers like PIN ?

Some pins is configured as outputs and relevant resistor ( PU/PD) keep state when MCU in Powerdown mode.

But when after restoring we need to recover output state as well or output state follow resistor usage.

Regards,

Eugene

[Sabina_Bruce]

Hello Eugene,

Please keep communication regarding the same topic on one thread.

https://community.nxp.com/thread/523000 

Best Regards,

Sabina

[EugeneHiihtaja]

Hi sabinabruce‌ !

Can issue be tested on your side somehow ?

DIR register loze state for sure and all outputs converted back to inputs.

it is clear reproducable and may be Repeater mode is designed for support this issue :

"

The repeater mode enables the pull-up resistor if the pin is high and enables the
pull-down resistor if the pin is low. This causes the pin to retain its last known state if it is
configured as an input and is not driven externally. Such state retention is not applicable to
the deep power-down mode. Repeater mode may typically be used to prevent a pin from
floating and potentially using significant power if it floats to an indeterminate state if it is
temporarily not driven.

"

But it is not so clear but dumping state of pins before and after powerdown mode 

show this effect.

Regards,

Eugene