Factory ESP32 toggling pins not mentioned in docs?
Posted: Thu Jan 13, 2022 10:18 pm
We have built a new CNC controller that uses the ESP32. When we apply power to the board to program it starts triggering relays in the power section. This could be dangerous.
The pins affected are connected to GPIO 16 and 17.
Before we designed this board, we verified according to the docs that these GPIOs are not active during boot. We even tested them to verify this (they float) but I failed to test them with the factory image. That was my fault. Turns out, they do follow the docs but only if the part is erased. The factory image does change the state of the pins so be careful.
This is relevant if you plan on programming them after you have the parts installed from the reel.
The pins affected are connected to GPIO 16 and 17.
Before we designed this board, we verified according to the docs that these GPIOs are not active during boot. We even tested them to verify this (they float) but I failed to test them with the factory image. That was my fault. Turns out, they do follow the docs but only if the part is erased. The factory image does change the state of the pins so be careful.
This is relevant if you plan on programming them after you have the parts installed from the reel.