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Pull up does not work.

Posted: Fri Sep 20, 2024 10:36 am
by Saichander
The signal lines RWA_ALARM, NORMAL_BETRIEB are pulled up (at first internal pull up it did not worked and after that in the pcb I have externally pulled up as well) but the voltage level on those lines are around 1-1.5 volts.

If anyone knows the reason/solution please let me know. (if there are any mistakes which I did please let me know)

Thanks in advance.

Re: Pull up does not work.

Posted: Fri Sep 20, 2024 12:49 pm
by felmue
Hello @Saichander

have a look here: https://docs.espressif.com/projects/esp ... /gpio.html. GPIO34 to GPIO39 don't have internal pull-up (or pull-down) capabilities.

Excerpt from that page: GPI: GPIO34-39 can only be set as input mode and do not have software-enabled pullup or pulldown functions.

As for the external pull-ups - maybe they are too weak?

Thanks
Felix

Re: Pull up does not work.

Posted: Sat Sep 21, 2024 12:25 am
by ESP_Sprite
How is the schematic bit that derives those two signals supposed to work? If any, I don't see a way for the MOSFETs to stop conducting: as soon as they start conducting (and the gate capacitance is charged) there's no way for the gate capacitance to discharge again.