Controlling your World the Easy Way

Yay! I get to answer my own question Again. In the Espressif manual, Appendix A - ESP32 Pin Lists A.1.2 -- GPIO pins 34-39 are input-only. GPIO pins 34-39 are input-only. These pins do not feature an output driver or internal pull-up/pull-down circuitry. The pin names are: SENSOR_VP (GPIO36), SENSOR...

I can't seem to digitalWrite IO34,35,36,39 Is there something special about them? I wrote a 'blinker' and they won't budge. #define csP1 34 #define csP2 35 #define csP3 36 #define csP4 39 #define miso 12 #define mon 16 void setup() { pinMode(csP1, OUTPUT); pinMode(csP2, OUTPUT); pinMode(csP3, OUTPUT...

OK, I found the answer - in the Espressif datasheet.
GPIO2 is a "strapping pin" and its condition determines the boot state.
(GPIO5 is a "strapping pin", too.)

It's all there in 2.4
https://www.espressif.com/sites/default ... eet_en.pdf

I have found that a sketch (Arduino IDE) will not Upload with an LED between +3V and GPIO2. It's OK with an LED between +3 and GPIO4 though. "A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header If it's a red LED then it bombs; if it's a yellow LED then it's O...

I'm finding that the LEDs don't turn OFF, but stay on if dimly, with dutyCycle = 255 (they're pulled up, so full on is 0).

How can I effect full off? Once a GPIO gets "attached" [ledcAttachPin(ledPin, ledChannel);], how can I "unAttach"?