ESP32 LCD Driver

Description

This repository contains a custom lcd driver for 16x02 lcd. The driver has the most common function calls that are use for LCDs. ESP32 have limited GPIO pins, therefore 4-bit mode was use as it requires a total of 6 GPIO pins. However, there are two configurations for the driver: default and custom. The default configurations uses this pinout while the custom allows the user to select whichever GPIO are avaiable simple by using lcdCtor().

ESP32 Pinout

                                        +-----------------------+
                                        | O      | USB |      O |
                                        |        -------        |
                                    3V3 | [ ]               [ ] | VIN
                                    GND | [ ]               [ ] | GND
    Touch3 / HSPI_CS0 / ADC2_3 / GPIO15 | [ ]               [ ] | GPIO13 / ADC2_4 / HSPI_ID / Touch4
CS / Touch2 / HSPI_WP / ADC2_2 /  GPIO2 | [ ]               [ ] | GPIO12 / ADC2_5 / HSPI_Q / Touch5
     Touch0 / HSPI_HD / ADC2_0 /  GPIO4 | [ ]               [ ] | GPIO14 / ADC2_6 / HSPI_CLK / Touch6
                        U2_RXD / GPIO16 | [ ]               [ ] | GPIO27 / ADC2_7 / Touch7
                        U2_TXD / GPIO17 | [ ]               [ ] | GPIO26 / ADC2_9 / DAC2
                     V_SPI_CS0 /  GPIO5 | [ ]  ___________  [ ] | GPIO25 / ADC2_8 / DAC1
               SCK / V_SPI_CLK / GPIO18 | [ ] |           | [ ] | GPIO33 / ADC1_5 / Touch8 / XTAL32
       U0_CTS / MSIO / V_SPI_Q / GPIO19 | [ ] |           | [ ] | GPIO32 / ADC1_4 / Touch9 / XTAL32
                SDA / V_SPI_HD / GPIO21 | [ ] |           | [ ] | GPIO35 / ADC1_7 
                 CLK2 / U0_RXD /  GPIO3 | [ ] |           | [ ] | GPIO34 / ADC1_6 
                 CLK3 / U0_TXD /  GPIO1 | [ ] |           | [ ] | GPIO39 / ADC1_3 / SensVN 
       SCL / U0_RTS / V_SPI_WP / GPIO22 | [ ] |           | [ ] | GPIO36 / ADC1_0 / SensVP 
               MOSI / V_SPI_WP / GPIO23 | [ ] |___________| [ ] | EN 
                                        |                       |
                                        |  |  |  ____  ____  |  |
                                        |  |  |  |  |  |  |  |  |
                                        |  |__|__|  |__|  |__|  |
                                        | O                   O |
                                        +-----------------------+

LCD 16x02 Pinout

The following pinout is the default configuration of the ESP-LCD driver. However, the driver is customizable to allow users to change GPIO pins if necessary.

ESP32 Pins	LCD Pin	Description
GND, 10k Potentiometer Output (V±)	1	GND
VCC, 10k Potentiometer Output (V±)	2	VCC
10k Potentiometer Output (Vo)	3	Contrast
GPIO23	4	RS (Register Select): 0–Command, 1-Data
GND	5	R/W (Read/Write): 0 – Write, 1 - Read
GPIO22	6	Clock Enable
NC	7	Data 0
NC	8	Data 1
NC	9	Data 2
NC	10	Data 3
GPIO19	11	Data 4
GPIO18	12	Data 5
GPIO17	13	Data 6
GPIO16	14	Data 7
100Ω to VCC	15	Backlight Anode (+)
GND	16	Backlight Cathode (-)

• LCD default pin configuration

LCD Main Functions

Function	Description
lcdDefault()	Default pinout
lcdCtor()	Customizable pinout constructor
lcdSetText()	Set text
lcdSetInt()	Set integer
lcdClear()	Clear previous data
lcdFree()	Free LCD pins
assert_lcd()	Check lcd status

Simple Example Code

The follow section of code demostrate how to use the lcd driver with default configuration.

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/esp_lcd.h"
 
/* LCD task */
void lcd_task(void *pvParameters){
 
  /* Create LCD object */
  lcd_t lcd;
 
  /* Set lcd to default pins */
  lcdDefault(&lcd);
 
  /* Initialize LCD object */
  lcdInit(&lcd);
 
  /* Clear previous data on LCD */
  lcdClear(&lcd);
 
  while(1){
    /* Display text */
    lcdSetText(&lcd, "Hello World!", 0,0);
    /* 1 second delay */
    vTaskDelay(1000 / portTICK_PERIOD_MS);
  }
 
}
 
void app_main(void)
{
  
  /* Create LCD task */
  xTaskCreate(lcd_task, "LCD task", 2048, NULL, 4, NULL);
 
}

ESP32 LCD Driver Test

Add ESP-LCD to ESP32 Project

1) Copy driver folder 2) Paste into esp project 3) Edit project CMakeLists.txt to use esp_lcd:

idf_component_register(SRCS "main.c"
                            "driver/esp_lcd.c"
                    INCLUDE_DIRS ".")

Development

Microcontroller	Software	Enviroment	Operating System

License and Release

License	Release

Author

• Jesus Minjares
  
  • Master of Science in Computer Engineering