ESP8266 project to retrieve date and time from an NTP server. I worked on Mac OS and i used the Arduino IDE to program directly the ESP8266-01 module.
- ESP8266-01
- USB to Serial adapter with the FT232RL (FTDI) chip
- 3.3V power supply
- Breadboard and some jumper wires
- 2x10KΩ resistors
You can also use a USB to Serial adapter with CH340 chip
ESP8266-01
------------------
VCC -> 3.3V (power supply)
CH_EN -> 3.3V (power supply through 10kΩ)
RST -> 3.3V (power supply through 10KΩ)
TX -> RX (FTDI)
RX -> TX (FTDI)
GPIO0 -> *
GPIO2 -> NC
GND -> GND (power supply)
*The GPIO0 needs to be connected to GND to enter boot mode and NC to run regularly.
NC = Not Connected
FTDI Adapter
-----------------
VCC -> NC
GND -> GND (power supply)
TXD -> RX (ESP8266)
RXD -> TX (ESP8266)
RTS -> NC
CTS -> NC
It's important to have a common GND, so connect both GNDs to the power supply.
Install the Arduino IDE from the link above, then install the esp8266 board package: go to Tools -> Board -> Board Manager, search for "esp8266" and download the latest version. After installing that, select the "Generic ESP8266 Module" from Tools -> Board -> "ESP8266 Boards (version)".
For the esptool just follow the "Easy installation" from the link above, which is the official documentation.
Then download the "bin" directory and move it inside the directory "esptool-master", just downloaded with the esptool installation.
To communicate with the ESP8266 connect the FTDI adapter to your pc and from the Arduino IDE select the right port in Tools -> Port. The default baud of the ESP8266 is 115200 (sometimes 74880), so open the serial monitor and select 115200 baud and Both (NL and CR), type:
AT
if the esp responds with "OK" everything is working fine, otherwise check again the connection. Now open a terminal window, then connect the GPIO0 to GND and write the following commands:
cd <path to directory "esptool-master">
Erase the flash of the esp8266:
./esptool.py erase_flash
If a timeout error occurs, pull the RST pin to GND while the esp is on and try again. Flash the new firmware "esp8266_nonos_sdk_v2.0.0_16_08_10", make sure that the "bin" directory is in the right path:
./esptool.py --port /dev/tty.<usbserial> write_flash 0x00000 bin/eagle.flash.bin 0x78000 bin/blank.bin 0x7c000 bin/esp_init_data_default.bin 0x7a000 bin/blank.bin 0x7e000 bin/blank.bin 0x10000 bin/eagle.irom0text.bin -fm dout
to find your <usbserial> just double click tab or read it on the Arduino IDE Ports menu. Now disconnect GPIO0 from GND and leave it NC. The communication between the Arduino nano and the esp8266 can be established only with a baudrate of 9600, so to change the baudrate of the esp from 115200 to 9600 in the serial monitor write:
AT
if the esp responds with "OK" everything is working fine, otherwise check again the connection, then write:
AT+UART_DEF=9600,8,1,0,0
Now change again the serial monitor baudrate, select 9600 baud and Both (NL and CR). Finally reconnect GPIO0 to GND and flash the Arduino program "NTP_esp.ino" using the Arduino IDE. In the Tools menu select:
Board: Generic esp8266 module
Upload Speed: 115200
Flash Mode: DOUT
And leave the rest as it is, now hit the upload button and wait. After it's finished, disconnect the GPIO0 and using the serial monitor check that everything's working fine.
If you change wifi ssid or pwd you'll have to repeat the whole process, because re-uploading the arduino program wont' work. This is a problem related to the esp8266-01 module because it saves the credentials in its memory https://arduino-esp8266.readthedocs.io/en/latest/esp8266wifi/readme.html ("Station" paragraph).