ESP-01 (ESP8266) Circuit Design Tutorial: Power, Enable, Reset & GPIO Usage

 Essential Pins for Circuit Design

Following connections are required around the ESP-01 module.

• The operating voltage of ESP8266 is 2.5 V to 3.6 V. 3.3V is the preferable voltage as it is compatible with widely available boards

• The CH_PD pin is the CHIP ENABLE pin of ESP8266, it has to be pulled HIGH. We can pull it up with a weak pull-up. In the above circuit, we have shown 10K resistor, the value can be much higher. We tested with 10K and suggesting the same.

• To have the ESP-01 in programming mode, GPIO0 must be pulled LOW. So, include a switch between GND and GPIO0, Once programming is done, the switch can be made OPEN. GPIO0 has internal pull-up, so, that will suffice to keep the pin HIGH. Keeping GPIO0 HIGH enables normal mode of the ESP8266. Ensure that the GPIO0 is pulled LOW before power ON so that the module enters programming mode.
• Programming of ESP8266 has to be done through UART pins - TX, RX. So, connect TX, RX to either Arduino Uno or a USB to UART converter for programming. There are adapter boards available like the one below. The adapter will have all the connections, we mentioned above.

• Check below link for some of the lessons learnt while programming ESP-01 module

https://embeddeddesignblog.blogspot.com/2025/12/esp-01-esp8266-module-complete.html

• Explanation of the above in our Youtube channel - Way2know

https://youtu.be/aAhuIJ1__CY

With the correct power design, pull-ups, and boot mode configuration, the ESP-01 module becomes a powerful WiFi-enabled embedded system building block.

Tags: ESP-01, ESP8266, ESP8266 circuit, ESP-01 schematic, ESP-01 design, ESP8266 GPIO, ESP-01 programming, WiFi module design, ESP8266 hardware