It is better to use pull up resistor with GPIO0 in ESP8266 ESP-01

In ESP8266, GPIO has two two functionalities.

Low state: To keep the ESP8266 in firmware flash mode 

High state: To keep the ESP8266 in normal working mode

Open state: Works same as High state

Problem in keeping the GPIO0 in open state: Sometimes during boot, the device do not recognize GPIO0 as high/Low state and the device do not boot up properly.

Solution: while working in normal mode, use 1K resister with GPIO0 and make it high by connecting with power supply.

How to connect ESP8266 ESP-01 and USB to serial converter CP2120 Silicon Labs

ESP8266 ESP-01 module has UART to communicate with PC or other microcontroller.

The communication happens in two ways:
Normal working mode: Send AT commands from serial software like Hyperterminal.
Firmware flash mode: Communicate with PC to Flash firmware (AT, NodeMCU etc.) using flash software.

Video tutorial:

Normal working mode:

Please use the following steps:


1. Connect VCC and GND pin of the module with 3.3V power supply.
2. Connect RXD of the module with TXD of USB to serial convertet.
3. Connect TXD of the module with RXD of USB to serial converter.
4. Connect CH_PH of the module with VCC of 3.3V power supply.
5. Connect GND of the module with GND of USB to serial converter.

Note: Please keep GPIO0 & GPIO2 open. Do not connect with either VCC or GND.


Firmware flash mode:

All other connections are same as Normal mode. Only one more connection require to put the module in Firmware Flash mode.

Connect GPIO0 of the module with GND of 3.3V Power supply.







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How to Flash AT commands firmware in ESP8266 ESP-01 Wi-Fi module

Flash AT commands firmware in ESP8266 ESP-01 device

The module comes with AT commands firmware when buy but you can flash other firmware into the module like NodeMCU etc. 

But if we want to reflash Espressif's AT commands firmware again in the Wi-Fi module it is very simple.

Do the following steps to download and Flash AT command firmware into the module:

1. Download Espressif's original ESP8266 Flasher.exe and ESP8266_AT_firmware.bin. Please click here to download.

2. Unzip the zip file.

3. Open ESP8266 flasher and add binary.

4. Connect ESP8266 ESP-01 with USB to serial converter. Connect GPIO0 to ground to put the module into flashing mode.

5. Click to flash the software.

6. Done!

How to put ESP-01 module into flashing mode:

Connect GPIO0 with Ground pin of power supply

Video:

ESP8266 ESP-01 Pin description, getting started with $4 cheapest Wi-Fi module

ESP8266 ESP-01 pin description

This module has total of 8 pins.

The module works in two modes:
Normal working mode
Firmware flash mode

Pin description :





Video

Thank you!