Hello,
I am using a HTCC-AB01 v2 board together with an ublox neo6M GPS module.
My goal is to have the board on for some minutes and then put everything into sleep for longer period of time. During the on period, I want to keep the GPS module always powered on, in order to save the time for GPS fix.
But Vext pin is going to low as soon as the MCU goes to deep sleep. Is there a way to hold the GPIOs in a HIGH state during the deep sleep?
Best regards
Perhaps a bit more details on the topic. I am specifically setting the Vext pin as output and only set it to LOW, but as soon as the mcu goes to sleep, Vext pin seems to go HIGH because of the pull-up resistor. I measured the voltage on the Ve pin. The voltage drops to 0V as soon as the MCU goes to sleep.
My best guess that the pins are (somewhere) configured as INPUT before sleep and it overrides what the user does.
Vext during sleep
I use the Vdd pin on the AB02 board to provide power to an external watchdog timer when the board is sleeping and Vext is off. You should be able to do something similar, using the 3.3V pin, with the AB01 board.
In between I have tested if other gpios are behaving the same as Vext. It seems that other gpios are holding the state that they had before sleeping, during the sleep. I could easily reproduce the Vext with another gpio, but I would like to avoid additional hardware. Vext is driven by goio6, so I guess it is a software related thing that might fix this “issue”. I have had a look inside the libraries, but so far I couldn’t find anything.