Arducam ESP8266 with OV5642

I am having an issue with the ESP8266 board. I have an application running on it however it will not restart if I disconnect the power and power it up again. If I power it up multiple times I can sometimes get it start the application. Most of the time I have to recompile to get the program to restart. I am planning on installing it in an inaccessible location and will not have the capability to recompile.

I am using the A0 and GPIO0 pins along with the OV5642 camera.

Is there something I can do? Is this a normal function of the board? Is there an update to fix this problem?


Usually the program is not working properly, you can try to press reset key.

However, if you are using GPIO0, make sure the GPIO0 pin level is high when power on the board. If it is low, the board will go into download mode.

What other GPIO pins are available on the ESP8266 board if you are using the OV5642 camera. If GPIO0 is not a good pin to use which is? I need to test when an input goes from low to High.

Question 2: What is the voltage range for the Analog pin? A0



In addition to GPIO0, I suggest you use GPIO2.

The voltage range of A0 is 0-5V.

Referring to the documentation guide for the ESP8266 at:
I found that GPIO2 is also used at boot.
per guide:
"Boot mode select - Don’t connect to ground at boot time Sends debug data at boot time.

What GPIO can I reliably use to test when a voltage goes from low to high. This is an Anemometer whose signal is High to low to High. I have no control as to where it will be at boot. Sitting at the top of 35 foot mast.

If I connect to GPIO0 and the input is sitting on low the program will not start. Looks like the same would be true for GPIO2.


Here is the schematic for ESP8266, where you can select unused pins to test.