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ESP32: Power On status of the pins during power-on/ boot up process.

Posted: Tue Jun 18, 2019 10:31 pm
by Yuvaraj1867
Hi Guys,

My project uses GPIO pins to drive PWM to control power to a load. The issue I am facing now is that the power-on-default value of the pins is driving the MOSFET fully on - this will damage my load as the current is uncontrolled. This condition exists until the boot up process is completed and firmware change the status of the selected pin.

Since the boot time is too large, we need a way to instruct the ESP32 MCU to keep the pins in the required condition during power-on / boot up process.

Can anyone please let me know how to do this?

Re: ESP32: Power On status of the pins during power-on/ boot up process.

Posted: Wed Jun 19, 2019 9:30 am
by Yuvaraj1867
Anybody help me because It is urgent.

Re: ESP32: Power On status of the pins during power-on/ boot up process.

Posted: Thu Jun 20, 2019 4:51 am
by ESP_Sprite
You could try to hack the bootloader to set the GPIOs as soon as possible.... but that would be a workaround at best. What GPIOs are your mosfets connected to? Can you move them to IOs that aren't used during boot, and add a pull-up / pull-down resistor to force them to the correct level around that time?

Re: ESP32: Power On status of the pins during power-on/ boot up process.

Posted: Thu Jun 20, 2019 5:12 am
by Yuvaraj1867
Hi

Thanks.

I don't know how to hack the bootloader. Can you help me.

i am using GPIO18 and GPIO19.

Re: ESP32: Power On status of the pins during power-on/ boot up process.

Posted: Thu Jun 20, 2019 7:24 am
by ESP_Sprite
18 and 19 aren't used by the chip on boot as far as I know. Do you have pullups/downs on the gates of your mosfets?

Re: ESP32: Power On status of the pins during power-on/ boot up process.

Posted: Thu Jun 20, 2019 11:11 am
by Yuvaraj1867
i will try to add pullup/pulldown.

Re: ESP32: Power On status of the pins during power-on/ boot up process.

Posted: Thu Jun 20, 2019 2:52 pm
by WiFive