Tech Note 068 - Arduino IDE how to Determine, Add and Change Pin Mapping

Confused about Arduinio, ESP8266 and ESP32 pin maps on development boards, here's how to find out what those pin labels mean and how they are mapped to GPIO pins. Also I show how to add your own pin definitions and change pins.

Arduinio:
ArduinoIDE\libraries\Firmata\Boards.h

[stahme]

Thanks for sharing your research and the Great job of presentation and graphics.

[VideoDetection]

Well done, very helpful!
Fixed the flashing led on VSPI by changing CS pin definition. The sensor inputs were also a helpful hint for adding to the pins file.

[casholsen]

It's nice to fix these for ourselves, put how can these get them factored into the greater project. Just about every board would need to be expanded or fixed. But in this video you give me a starting place and a place to see how the pin was defined.

[VideoDetection]

One thing to mention is that the selection you made of PIN 2 for SS/CS in your SPI example has a bit of a catch. The catch being that PIN 2 needs to be held low during the sketch upload. I tried using pin 2 as SS for a ADXL345 project and the sketch would not load. I used PIN 16, (2RXD) for SS instead as I dont require any other function for this pin. Reassigned PIN 16 as SS and all works and loads perfectly.

Newcomers to this chip need to be aware of the pins used for boot and flash upload! Maybe a great subject for another of your Tech Note series :)

[GEJD]

Thanks, unfortunately in the latest IDE remapping pins is not quite so easy.

[dreamsbeyondreality]

How do you know which library goes with which pin variant? I've been using the ESP32 Dev Module board profile but do not see that in the variants folder. Any suggestions?
Nice video, btw

[mousefad]

I think the T prefix is for touch sensor pins.

[paveld]

Great video, how to change off some definition in Arduino of PINs and change into definitions for your need.

[SA-ojbo]

Hi David, interesting but I can not find the esp32\variants folder. Is it changed in the newest IDE version? 1.8.7
7

[uweri_]

I love your videos. For me it was a little bit hard to understand which pin will be used for what. But one more question. I use Board = ESP32 Dev Module. So definition should be found under folder doitESP32devkitV1. Correct ?