#Wire library for esp8266 how to#
#Wire library for esp8266 serial#
#Wire library for esp8266 code#
#Wire library for esp8266 download#
#Wire library for esp8266 free#

On the NodeMCU board, the ADC Pin is marked as A0. So, the output of the ADC will be a number in the range of 0 to 1023.Īlso note that ESP8266 has only one ADC Channel. If you remember the specifications of ESP8266, its internal ADC has a resolution of 10-bit. CodeĪs a bonus, I made a small circuit in which a 10 KΩ Potentiometer is connected to the ADC pins of NodeMCU (labelled A0) and display the result of ADC on the LCD using the I2C LCD Module. There are no extra connections as the previously made connections are all that we need.

#Wire library for esp8266 how to#

Now, let us see how to display a simple text on the 16×2 LCD using ESP8266 and I2C LCD Module.

we have to use this slave address in the main code.

#Wire library for esp8266 serial#

CodeĮSP8266 will look for any slaves and if a slave acknowledges, it gets its slave address and prints it on the serial monitor.

#Wire library for esp8266 code#

After making all the connections, upload the code to ESP8266 NodeMCU and open the serial monitor. So, let us use the following code to get the slave address of the I2C LCD Module. Here, the ESP8266 NodeMCU is the I 2C Bus master and the PCF8574 I2C LCD Module is the slave. If you remember basics of I 2C Communication, a master can communicate with a slave only if it knows the slave address. Getting the Slave Address of I2C LCD Moduleīefore writing the actual code to display stuff on the LCD, we have to first determine the Slave Address of the PCF8574 I2C LCD Module. Make sure that NodeMCU is selected in the boards and also set the right COM Port. Now, make all the necessary connections as mentioned before and plug in the ESP8266 NodeMCU to the computer. So, you can see that it is already installed for me. I used this library in a couple of previous projects.

#Wire library for esp8266 download#

Search for “liquidcrystal i2c” and download the “LiquidCrystal I2C” library by Frank de Brabander. Open Arduino IDE and go to Tools -> Manage Libraries. If you haven’t worked with I2C LCD Module before, then you have to download a special library. The following image shows the circuit diagram of ESP8266 NodeMCU I2C LCD Interface. So, even though PCF8574 IC works at 2.5 V to 6 V supply, instead of giving 3.3V from the NodeMCU, we are giving 5V. NOTE: The LCD Display works on a supply voltage between 4.7 V and 5.3 V. The following table shows the connections between I2C LCD Module and ESP8266 NodeMCU. You only need to provide the supply and I 2C connections. There are no other connections between I2C LCD Module and the actual LCD itself as the Module simply plugs into the pins of the LCD Display. We have to use these two pins to connect to PCF8574 I2C LCD Module. If you remember the pinout of ESP8266 NodeMCU, D1 and D2 i.e., GPIO 5 and GPIO 4 are frequently used for I 2C Communication.ĭ1 (GPIO 5) is the SCL Pin and D2 (GPIO 4) is the SDA Pin. Let us now understand how the ESP8266 NodeMCU I2C LCD Interface works.

So, its pinout coincides with a typical 16×2 LCD, it contains a potentiometer to adjust the contrast and also a jumper to enable or disable the backlight. Instead of GPIO expansion, the I2C LCD Module is dedicated to drive a character LCD. Originally, it is used in modules to expand the GPIO Pins of a Microcontroller and it communicated with the microcontroller through I 2C Interface. A Brief Look at PCF8574 I2C LCD ModuleĪs the name suggests, the PCF8574 I2C LCD Module is based on the PCF8574 GPIO Expander IC. Thus from 6 GPIO Pins, we have come down to two GPIO Pins (SDA and SCL of I 2C). It is designed specially for 16×2 and 20×4 Character LCD Displays and communicates through, well, I 2C interface. This is where the I2C LCD Module comes handy. Using that many GPIO Pins for a character LCD Display is not feasible, if you are planning to interface other important sensors and devices.

#Wire library for esp8266 free#

After taking out all the dedicated GPIO pins (for SPI Flash IC and UART) we get around 9 GPIO Pins free to use.īut what if you want to interface a 16×2 Character LCD Display with ESP8266 NodeMCU? Even in 4-bit Parallel communication mode, the 16×2 LCD will take up 6 GPIO Pins of the microcontroller (four for Data, one for RS and one for E). Another advantage of this board is the GPIO Pins. The ESP8266 NodeMCU is a great development board for Wi-Fi related applications.

Getting the Slave Address of I2C LCD Module.