esp-idf/examples/peripherals/lcd/tjpgd

LCD tjpgd example

(See the README.md file in the upper level 'examples' directory for more information about examples.)

Overview

This example shows how to decode a jpeg image and display it on an SPI-interfaced LCD, and rotates the image periodically.

If you want to adapt this example to another type of display or pinout, check lcd_tjpgd_example_main.c for comments with some implementation details.

How to Use Example

Hardware Required

• An ESP development board
• An SPI-interfaced LCD
• An USB cable for power supply and programming

Hardware Connection

The connection between ESP Board and the LCD is as follows:

      ESP Board                            LCD Screen
      +---------+              +---------------------------------+
      |         |              |                                 |
      |     3V3 +--------------+ VCC   +----------------------+  |
      |         |              |       |                      |  |
      |     GND +--------------+ GND   |                      |  |
      |         |              |       |                      |  |
      |   DATA0 +--------------+ MOSI  |                      |  |
      |         |              |       |                      |  |
      |    PCLK +--------------+ SCK   |                      |  |
      |         |              |       |                      |  |
      |      CS +--------------+ CS    |                      |  |
      |         |              |       |                      |  |
      |     D/C +--------------+ D/C   |                      |  |
      |         |              |       |                      |  |
      |     RST +--------------+ RST   |                      |  |
      |         |              |       |                      |  |
      |BK_LIGHT +--------------+ BCKL  +----------------------+  |
      |         |              |                                 |
      +---------+              +---------------------------------+

The GPIO number used by this example can be changed in lcd_tjpgd_example_main.c, where:

GPIO number	LCD pin
EXAMPLE_PIN_NUM_PCLK	SCK
EXAMPLE_PIN_NUM_CS	CS
EXAMPLE_PIN_NUM_DC	DC
EXAMPLE_PIN_NUM_RST	RST
EXAMPLE_PIN_NUM_DATA0	MOSI
EXAMPLE_PIN_NUM_BK_LIGHT	BCKL

Especially, please pay attention to the level used to turn on the LCD backlight, some LCD module needs a low level to turn it on, while others take a high level. You can change the backlight level macro EXAMPLE_LCD_BK_LIGHT_ON_LEVEL in lcd_tjpgd_example_main.c.

Extra connections for 8-line LCD (Octal SPI)

Firstly, please run idf.py menuconfig and set the Drive a LCD with 8 data lines option at Example Configuration.

Change the extra GPOIs used by octal SPI in lcd_tjpgd_example_main.c, where:

GPIO number	LCD pin
PIN_NUM_DATA1	D1
PIN_NUM_DATA2	D2
PIN_NUM_DATA3	D3
PIN_NUM_DATA4	D4
PIN_NUM_DATA5	D5
PIN_NUM_DATA6	D6
PIN_NUM_DATA7	D7

Build and Flash

Run idf.py -p PORT flash monitor to build, flash and monitor the project. A flowing picture will be shown on the LCD screen.

(To exit the serial monitor, type Ctrl-].)

See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.

Troubleshooting

For any technical queries, please open an [issue] (https://github.com/espressif/esp-idf/issues) on GitHub. We will get back to you soon.