Introduction: Flash AT Command Firmware to ESP01 Module (requires a USB to TTL Adapter)
Step 1: Get the Necessary Files
Step 2: Preparations for Flashing
1. Open "esp8266_flasher.exe"
2. Load the BIN File “ai-thinker-v1.1.1.bin”. You may check this link if you want a different version : http://wiki.aprbrother.com/wiki/Firmware_For_ESP8266
3. Type in the proper COM port, if you don’t know what’s the COM Port, head over to Device Manager >> Ports (COM & LPT), it should be there. If not, then there’s something wrong with your adapter.
To fix it, click here(There’s a part there that’ll guide you on how to reinstall the driver or you can google on your own, whatever suits you)
Step 3: Make the Connections
1. Make the following connections
a. USB to TTL Tx - ESP Rx
b. USB to TTL Rx - ESP Tx
c. USB to TTL 3.3V - ESP VCC & CH_PD (ESP01 is 5V intolerant!)
d. USB to TTL GND - ESP GND & GPIO0 (Take note of this pin, it should be removed when sending AT commands later on, for now just keep it plugged)
Then click Download
Step 4: Downloading
1.You should have something like this. If in the end it says, “failed to leave flash mode”, don’t worry. The flashing is already done by that time.
Step 5: Testing
1. After it’s done, open Arduino IDE. Select the proper COM Port in Tools >> Port
2. Before anything else, redo the connections by simply unplugging the GPIO0 (only this pin has to be removed)
a. USB to TTL Tx - ESP Rx
b. USB to TTL Rx - ESP Tx
c. USB to TTL 3.3V - ESP VCC & CH_PD
d. USB to TTL GND - ESP GND
3. Open the Serial Monitor (Both NL & CR, 115200 baud or sometimes trial and error will work, just try different combinations)
4. Type in “AT” (not case sensitive), then press Enter, it should return “Ok”
5. Done!
