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Easy Basics: Project 072t ESP32 Development board with LCD1602 I2C display module

of Acoptex.com in ESP8266 ESP-32

Basics: Project 072t

Project name: ESP32 Development board with LCD1602 I2C display module

Tags: Arduino, ESP32 Dev Module, ESP32 development board, ESP32 Development board with WiFi and Bluetooth, ESP32-DevKitC V4 development board, ESP-WROOM-32 module with ESP32‑D0WDQ6 chip, Espressif Systems, ESP32-based development board, ESP32 modules, ESP32-WROOM-32, ESP32-WROOM-32U, ESP32-WROOM-32D, ESP32-SOLO-1, USB-UART bridge, IOT, ESP-WROOM-32 Dev Module, ESP32 DEVKITV1, Installing the ESP32 Board in Arduino IDE, Uploading sketch, LCD1602, I2C, 16×2 I2C Liquid Crystal Display, LCD1602 I2C display module

Attachments: sketch1, sketch2, sketch3library1; sketch4, sketch5, library2

In this project, you need these parts :

1. ESP32 development board with WiFi and Bluetooth and USB A / micro USB B cable 1 pc

2.Arduino IDE ( you can download it from here  )

3.Jumper cables F-F

4. LCD1602 I2C display module 1 pc 

General

We will learn how to use the LCD1602 I2C display module with the ESP32 development board. 

There are a lot of different development boards made. You can find more information about them here

Understanding the LCD1602 I2C module

You can read more about it here.

Understanding the ESP32 Development board with WiFi and Bluetooth

We will discuss here an Espressif Systems products. Our development board is using ESP-WROOM-32 module from Espressif Systems.

Espressif offers a wide range of fully-certified Wi-Fi & BT modules powered by their own advanced SoCs.

1. Dual-core Modules with Wi-Fi & Dual-mode Bluetooth

Features

  • Two independently-controlled CPU cores with adjustable clock frequency, ranging from 80 MHz to 240 MHz
  • +19.5 dBm output at the antenna ensures a good physical range
  • Classic Bluetooth for legacy connections, also supporting L2CAP, SDP, GAP, SMP, AVDTP, AVCTP, A2DP (SNK) and AVRCP (CT)
  • Support for Bluetooth Low Energy (BLE) profiles including L2CAP, GAP, GATT, SMP, and GATT-based profiles like BluFi, SPP-like, etc
  • Bluetooth Low Energy (BLE) connects to smart phones, broadcasting low-energy beacons for easy detection
  • Sleep current is less than 5 μA, making it suitable for battery-powered and wearable-electronics applications
  • Integrates 4 MB flash
  • Peripherals include capacitive touch sensors, Hall sensor, low-noise sense amplifiers, SD card interface, Ethernet, high-speed SPI, UART, I2S and I2C
  • Fully certified with integrated antenna and software stacks

2. Single-core Modules with Wi-Fi & Dual-mode Bluetooth

Features

  • High-performance 160 MHz single-core CPU
  • +19.5 dBm output at the antenna ensures a good physical range
  • Classic Bluetooth for legacy connections, also supporting L2CAP, SDP, GAP, SMP, AVDTP, AVCTP, A2DP (SNK) and AVRCP (CT)
  • Support for Bluetooth Low Energy (BLE) profiles including L2CAP, GAP, GATT, SMP, and GATT-based profiles like BluFi, SPP-like, etc
  • Bluetooth Low Energy (BLE) connects to smart phones, broadcasting low-energy beacons for easy detection
  • Sleep current is less than 5 μA, making it suitable for battery-powered and wearable-electronics applications
  • Peripherals include capacitive touch sensors, Hall sensor, low-noise sense amplifiers, SD card interface, Ethernet, high-speed SPI, UART, I2S and I2C
  • Fully certified with integrated antenna and software stacks

3. Single-core Modules with 802.11b/g/n 2.4 GHz Wi-Fi

Features

  • High-performance 160 MHz single-core CPU
  • +19.5 dBm output at the antenna ensures a good physical range
  • Sleep current is less than 20 μA, making it suitable for battery-powered and wearable-electronics applications
  • Peripherals include UART, GPIO, I2C, I2S, SDIO, PWM, ADC and SPI
  • Fully certified with integrated antenna and software stacks

There are different development Boards made by Espressif Systems and other manufacturers. We will publish some information about Espressif Systems boards but you can also find out more information about other development boards here.

1. 2.4 GHz Wi-Fi & BT/BLE Development Boards

Features

  • PC connectivity: USB
  • Power supply options: USB (by default), or 5V/GND header pins, or 3V3/GND header pins
  • SDK: ESP-IDF source code and example applications

2. 2.4 GHz Wi-Fi Development Boards

Features

  • PC connectivity: USB
  • SDK: ESP8266 SDK source code and example applications

3. 2.4 GHz Wi-Fi + BT/BLE + Sensor Development Boards

Features

  • PC connectivity: USB
  • SDK: ESP-IOT-SOLUTION source code and example applications

You can find more information (datasheets, schematics, pins descriptions, functional desgn descriptions) about each board by pressing Getting started link close to each board here.

ESP32 chip

ESP32 is a series of low cost, low power system on a chip microcontrollers with integrated Wi-Fi and dual-mode Bluetooth. The ESP32 series employs a Tensilica Xtensa LX6 microprocessor in both dual-core and single-core variations and includes in-built antenna switches, RF balun, power amplifier, low-noise receive amplifier, filters, and power management modules. ESP32 is created and developed by Espressif Systems, a Shanghai-based Chinese company, and is manufactured by TSMC using their 40 nm process. It is a successor to the ESP8266 microcontroller.

ESP32 can perform as a complete standalone system or as a slave device to a host MCU, reducing communication stack overhead on the main application processor. ESP32 can interface with other systems to provide Wi-Fi and Bluetooth functionality through its SPI / SDIO or I2C / UART interfaces.

ESP32 is highly-integrated with in-built antenna switches, RF balun, power amplifier, low-noise receive amplifier, filters, and power management modules. ESP32 adds priceless functionality and versatility to your applications with minimal Printed Circuit Board (PCB) requirements.

ESP32 is capable of functioning reliably in industrial environments, with an operating temperature ranging from –40°C to +125°C. Powered by advanced calibration circuitries, ESP32 can dynamically remove external circuit imperfections and adapt to changes in external conditions.

Engineered for mobile devices, wearable electronics and IoT applications, ESP32 achieves ultra-low power consumption with a combination of several types of proprietary software. ESP32 also includes state-of-the-art features, such as fine-grained clock gating, various power modes and dynamic power scaling.

Functional Block Diagram:

Features of the ESP32 include the following:

Processors:

  • CPU: Xtensa dual-core (or single-core) 32-bit LX6 microprocessor, operating at 160 or 240 MHz and performing at up to 600 DMIPS
  • Ultra low power (ULP) co-processor
  • Memory: 520 KiB SRAM

Wireless connectivity:

  • Wi-Fi: 802.11 b/g/n
  • Bluetooth: v4.2 BR/EDR and BLE

Peripheral interfaces:

  • 12-bit SAR ADC up to 18 channels
  • 2 × 8-bit DACs
  • 10 × touch sensors (capacitive sensing GPIOs)
  • Temperature sensor
  • 4 × SPI
  • 2 × I²S interfaces
  • 2 × I²C interfaces
  • 3 × UART
  • SD/SDIO/CE-ATA/MMC/eMMC host controller
  • SDIO/SPI slave controller
  • Ethernet MAC interface with dedicated DMA and IEEE 1588 Precision Time Protocol support
  • CAN bus 2.0
  • Infrared remote controller (TX/RX, up to 8 channels)
  • Motor PWM
  • LED PWM (up to 16 channels)
  • Hall effect sensor
  • Ultra low power analog pre-amplifier

Security:

  • IEEE 802.11 standard security features all supported, including WFA, WPA/WPA2 and WAPI
  • Secure boot
  • Flash encryption
  • 1024-bit OTP, up to 768-bit for customers
  • Cryptographic hardware acceleration: AES, SHA-2, RSA, elliptic curve cryptography (ECC), random number generator (RNG)

Power management:

  • Internal low-dropout regulator
  • Individual power domain for RTC
  • 5uA deep sleep current
  • Wake up from GPIO interrupt, timer, ADC measurements, capacitive touch sensor interrupt

You can find ESP32 chip datasheet here, hardware design here, technical reference manual here.

Signals and connections of the LCD1602 I2C module

As you can see on the back of LCD 1602 I2C module there 4 connections: GND (-), VCC (+5V), Serial Data Line (SDA) (Arduino Uno SDA or Analog pin A4) and Serial Clock Line (SCL) (Arduino Uno SCL or Analog pin A5).

Signals and connections of the ESP32 Development board with WiFi and Bluetooth

You can find more information (datasheets, schematics, pins descriptions, functional desgn descriptions) about each board (made by Espresiff Systems) by pressing Getting started link close to each board here.

Let's check our development board - ESP32 DEVKITV1 with ESP-WROOM-32 module from Espressif Systems:

Pinout diagram for the ESP Wroom 32 breakout:

ESP32-WROOM-32 - ESP32-WROOM-32 module soldered to the development board. Optionally ESP32-WROOM-32D, ESP32-WROOM-32U or ESP32-SOLO-1 module may be soldered instead of the ESP32-WROOM-32.

USB-UART Bridge - A single chip USB-UART bridge provides up to 3 Mbps transfers rates.

BOOT button - Download button: holding down the Boot button and pressing the EN button initiates the firmware download mode. Then user can download firmware through the serial port.

EN button - Reset button: pressing this button resets the system.

Micro USB Port - USB interface. It functions as the power supply for the board and the communication interface between PC and the ESP module.

TX0, TX2 - transmit pin. GPIO pin

RX0, RX2  - receive pin.  GPIO pin

3V3 (or 3V or 3.3V) - power supply pin (3-3.6V). 

GND - ground pin.

EN - Chip enable. Keep it on high (3.3V) for normal operation.

Vin - External power supply 5VDC.

Wiring

LCD1602 I2C display module uses I2C communication which makes the wiring very simple. We are using the ESP32 default I2C pins (GPIO 21 (SDA) and GPIO 22 (SCL)).

LCD1602 I2C ESP32

GND                 GND

VCC                 VIN

SDA                 GPIO 21

SCL                 GPIO 22

Step by Step instruction

The ESP32 is currently being integrated with the Arduino IDE like it was done for the ESP8266. There’s an add-on for the Arduino IDE that allows you to program the ESP32 using the Arduino IDE and its programming language.

  1. Download and install the latest Arduino IDE Windows Installer from arduino.cc
  2. Download and install Git and Git GUI from git-scm.com
  3. Search for Git GUI, right-click the icon and select “Run as administrator
  4. Select the Clone Existing Repository option.
  5. Select source and destination. Source Location: https://github.com/espressif/arduino-esp32.git
  6. Target Directory:C:/Users/[YOUR_USER_NAME]/Documents/Arduino/hardware/espressif/esp32
  7. Do not create the espressif/esp32 folders, because they will be created automatically.
  8. Click Clone to start cloning the repository.Wait a few seconds while the repository is being cloned.
  9. Open the folder: C:/Users/[YOUR_USER_NAME]/Documents/Arduino/hardware/espressif/esp32/tools
  10. Right-click the get.exe file and select “Run as administrator“.
  11. You will see that necessary files will be downloaded and upzipped. It will take some time.
  12. When get.exe finishes, you should see the following files in the directory.
  13. Do wiring.
  14. Plug the ESP32 development board to your PC and wait for the drivers to install (or install manually any that might be required).
  15. Open Arduino IDE. 
  16. Open Boards manager. Go to Tools -> Board -> Boards Manager… (in our case it’s the DOIT ESP32 DEVKIT V1)
  17. Select COM port that the board is attached to (if you don’t see the COM Port in your Arduino IDE, you need to install the ESP32 CP210x USB to UART Bridge VCP Drivers)
  18. Find your LCD1602 I2C address. Each device has an I2C address that it uses to  accept commands or send messages. Compile and upload the sketch1 to your ESP32 development board. If everything went as expected, you should see a “Done uploading” message. (You need to hold the ESP32 on-board Boot button while uploading).
  19. Press the ESP32 on-board EN button to reboot it. 
  20. Open the Serial Monitor at a baud rate of 115200. Arduino will scan the address range looking for a reply.  Even though the documentation said it was 0x27, this scanner can detect different (in our case 0x3F)
  21. If you want to display static text on the LCD all you have to do is select where you want the characters to be displayed on the screen, and then send the message to the display. Let's upload a very simple sketch example that displays “Hello, World!“. Modify the sketch2 in attachments above (you can use the sketch below too): the line LiquidCrystal_I2C lcd(0x3F, lcdColumns, lcdRows); (See part marked bold). Compile and upload the sketch2 to your ESP32 development board. If everything went as expected, you should see a “Done uploading” message. (You need to hold the ESP32 on-board Boot button while uploading).
  22. Press the ESP32 on-board EN button to reboot it. 
  23. Note: You can use built-in potentiometer to adjust the contrast between the background and the characters on the LCD. On a “regular” LCD you need to add a potentiometer to the circuit to adjust the contrast.Press the ESP32 on-board EN button to reboot it. 
  24. Let's check another example on how to display scrolling text which is very useful when you want to display messages longer than 16 characters. The library comes with built-in functions that allows you to scroll text. The following sketch3 displays a static message in the first row and a scrolling message longer than 16 characters in the second row.
  25. Modify the sketch3  in attachments above (you can use the sketch below too): the line LiquidCrystal_I2C lcd(0x3F, lcdColumns, lcdRows); (See part marked bold). Compile and upload the sketch3 to your ESP32 development board. If everything went as expected, you should see a “Done uploading” message. (You need to hold the ESP32 on-board Boot button while uploading).
  26. Press the ESP32 on-board EN button to reboot it. 

  27. sketch4 and sketch5 are the same as sketch2 and sketch3 but we are using modified library and initialize the lcd with SDA and SCL pins.

Code

Sketch2. This code works well to display static text no longer than 16 characters. You need to include the LiquidCrystal_I2C library #include . Then set the number of columns and rows of your LCD display int lcdColumns = 16;int lcdRows = 2; Set the display address, the number of columns and number of rows. You should use the display address you’ve found LiquidCrystal_I2C lcd(0x3F, lcdColumns, lcdRows); In the setup(), first initialize the display with the init() method lcd.init(); Then, turn on the LCD backlight, so that you’re able to read the characters on the display lcd.backlight(); To display a message on the screen, first you need to set the cursor to where you want your message to be written. In the following line, we set the cursor to the first column, first row. lcd.setCursor(0, 0); Note: 0 corresponds to the first column, 1 to the second column… Finally you can print your message on the display using the print() method lcd.print("Hello, World!"); We wait one second, and then we clean the display with the clear() method lcd.clear(); After that, we set the cursor to a new position: first column, second row

lcd.setCursor(0,1); and the process repeated. 

sketch3. The code is quite well explained in previous section. Let's have a look at the newly created function: scrollText(). It has arguments:

  • row: row number where the text will be display
  • message: message to scroll
  • delayTime: delay between each character shifting. big delay times will result in slower text shifting, and small delay times will result in faster text shifting.
  • lcdColumns: number of columns of your LCD

We are displaying the messageToScroll variable in the second row (1 - the second row), with a delay time of 250 ms  scrollText(1, messageToScroll, 250, lcdColumns);

sketch4. Same as sketch2 but we are using modified library. The ESP32 default I2C pins (GPIO 21 (SDA) and GPIO 22 (SCL)).

lcd.begin(21, 22);// initialize the lcd with SDA and SCL pins 

sketch5. Same as sketch3 but we are using modified library. The ESP32 default I2C pins (GPIO 21 (SDA) and GPIO 22 (SCL)).

lcd.begin(21, 22);// initialize the lcd with SDA and SCL pins 

Troubleshooting

If you cannot compile the sketch you may need to move out the Liquid Cristal library from Arduino\libraries folder.

Summary

We have learnt how to use the LCD1602 I2C display module with the ESP32 development board. 

Libraries

  • All libraries attached on the begining of this project description.
  • Wire library included in your Arduino IDE.
  • LiquidCrystal_I2C library included.Download, unzip  and add to libraries in our PC, for example C:\Users\toshiba\Documents\Arduino\libraries. This link you can find in Preferences of Adruino IDE program which installed in your PC. You can read more about it here.
  • LiquidCrystal_I2C modified library included.Download, unzip  and add to libraries in our PC, for example C:\Users\toshiba\Documents\Arduino\libraries. This link you can find in Preferences of Adruino IDE program which installed in your PC. You can read more about it here.

Sketch

  • See attachments on the begining of this project


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Published at 02-09-2018
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