The example uses the LT9611 at 1920x1080@60 Hz in RGB565. It displays a full-screen LVGL dashboard using DMA2D and partial draw buffers in internal RAM.

How to use the example

Hardware Required

An ESP32-P4 development board
An LT9611 DSI-to-HDMI bridge
An HDMI display and cable
A USB cable for power supply and programming

Hardware Connection

The connection between the ESP board, the LT9611 bridge, and the HDMI display is as follows:

       ESP Board                      LT9611 Bridge                    HDMI Display
+-----------------------+      +-------------------+          +-------------------+
|                   3V3 +------+ VCC               |          |                   |
|                       |      |                   |          |                   |
|             DSI_CLK_P +------+ DSI_CLK_P         |          |                   |
|             DSI_CLK_N +------+ DSI_CLK_N         |          |                   |
|            DSI_DAT0_P +------+ DSI_DAT0_P        |          |                   |
|            DSI_DAT0_N +------+ DSI_DAT0_N        |          |                   |
|            DSI_DAT1_P +------+ DSI_DAT1_P        |          |                   |
|            DSI_DAT1_N +------+ DSI_DAT1_N        |          |                   |
|                       |      |           HDMI OUT+----------+HDMI IN            |
|                   SDA +------+ SDA               |          |                   |
|                   SCL +------+ SCL               |          |                   |
|                 Reset +------+ Reset (optional)  |          |                   |
|                       |      |                   |          |                   |
+-----------------------+      +-------------------+          +-------------------+

Before building, update EXAMPLE_PIN_NUM_LCD_RST, EXAMPLE_I2C_NUM, EXAMPLE_PIN_NUM_SDA, and EXAMPLE_PIN_NUM_SCL in dsi_hdmi_bridge_example_main.c according to the board wiring.

The example powers VDD_MIPI_DPHY from LDO channel 3 at 2500 mV. Update EXAMPLE_MIPI_DSI_PHY_PWR_LDO_CHAN and EXAMPLE_MIPI_DSI_PHY_PWR_LDO_VOLTAGE_MV in the source according to the board power design.

Build and Flash

Run the following command to build, flash, and monitor the example:

idf.py -p PORT build flash monitor

The first build can take additional time while the Component Manager resolves the external bridge and LVGL dependencies.

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

See the Getting Started Guide for complete instructions.

Example Output

I (...) dsi_hdmi_bridge: MIPI D-PHY powered by LDO channel 3 at 2500 mV
I (...) dsi_hdmi_bridge: Initialize LVGL
I (...) dsi_hdmi_bridge: Starting LVGL task
I (...) dsi_hdmi_bridge: Displaying LVGL UI at 1920x1080

Troubleshooting

If the log shows:

E lcd.dsi: can't fetch data from external memory fast enough, underrun happens

the DSI bridge cannot fetch the framebuffer from PSRAM fast enough. Reduce PSRAM traffic, for example:

Disable PSRAM XIP (this example already does so for 1080p60 RGB565)
Keep LVGL draw buffers in internal RAM instead of PSRAM
Avoid other large PSRAM allocations or DMA while the display is running

For technical questions, please open an issue.