Intro to ESP32

Wednesday, May 17, 2023

An Introductory Guide to the ESP32 Board

Orientation

This is an orientation guide to the ESP 32 breakout board, specifically the ESP32 DEVKIT V1. The pin functionalities and button purposes are described in the Functionality section. 

The board is rectangular, approximately 3 cm by 5 cm. There are mounting holes 3mm in diameter, on all 4 corners. 

Orient the board so that the side with the mounted components is facing upwards, and the short edge with the USB micro-b port is furthest from you. Two small buttons flank the left and right sides of the USB port. To the left of the USB port is the BOOT button. To the right is the EN button. 

There are 15 pins on the two long edges of the board, for 30 pins total.

On the left side of the board, proceeding from the upper left corner furthest from you to the lower left corner closest to you, the 15 pins are as follows:

3V3, GND, D15, D2, D4, RX2, TX2, D5, D18, D19, D21, RX0, TX0, D22, and lastly D23.

On the right side of the board, starting in the upper right corner furthest from you (right of the EN button, below the mounting hole) and proceeding towards you, the pins are as follows. VIN, GND, D13, D12, D14, D27, D26, D25, D33, D32, D35, D34, VN, VP, finishing with the EN pin in the lower left corner. (Not to be confused with the EN button) 

The other surface-mounted components on the board include the raised square metal housing covering the chip at the near end of the board. There is a divot on the upper right to note the chip’s orientation. On the near side of that housing is a raised rectangle that contains the antenna for the wifi and Bluetooth connection. On the far end of the board between the chip housing and the USB port, are other surface-mounted components including resistors, transistors, LEDs, etc.

Functionality

Last Minute Engineering has an in-depth guide to the pin-outs of the ESP32, while Random Nerd Tutorials has a nice overall introduction to the ESP32. A pin map is provided in the linked pinout table below.

Furthest from you there are two power pins, VIN on the right, and 3.3V on the left. There are two ground pins, one on each side, 2nd furthest from you. The EN pin is enable and is on the lower right, closest to you.

There are 25 GPIO (general purpose input output) pins - on the left side, these include all pins apart from GND and 3V3. On the right side these include all pins apart from VIN, GND, and EN. It should be noted that right-side pins D35, D34, VN, and VP are input only. All GPIO pins are PWM. 

There are 15 ADC (analog to digital converter) pins. All pins on the right side (apart from VIN, GND, and EN) are ADC. On the left side pins D15, D2, and D4 are also ADC. 

There are 9 touch pins, 6 on the right, and 3 on the left.

To access a google document with a table of the pinout arrangement, click here. Or you can click here for a PDF version of the pinout table.

Alternatively, click here for a large print PDF layout of the ESP32.