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ST LCD DSI MB1835

boards/shields/st_lcd_dsi_mb1835/doc/index.rst

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.. _st_lcd_dsi_mb1835:

ST LCD DSI MB1835 #################

Overview

The MB1835 shield (revision B-01) provides a 2.47-inch round TFT-LCD with MIPI DSI interface and capacitive touch screen, specifically designed for STM32U5G9J-DK1 Discovery kit.

The shield features:

  • 2.47-inch round TFT-LCD with 480x480 pixel resolution
  • 16.7M color depth (RGB888)
  • J025F1CN0201W display module with Himax HX8379C LCD controller
  • MIPI DSI® 2-data lane interface
  • Capacitive touch panel (CTP)
  • LED backlight with GPIO control

.. figure:: mb1835_front.webp :alt: MB1835 Display shield front image :align: center

MB1835 Display Shield Front Image

.. figure:: mb1835_back.webp :alt: MB1835 Display shield back image :align: center

MB1835 Display Shield Back Image

The MB1835 display board connects to the STM32U5G9J-DK1 through the CN1 connector:

+------+--------------+------------+-------+--------------+-----------------+ | CN1 | Description | Interface | CN1 | Description | Interface | | odd | | | even | | | +======+==============+============+=======+==============+=================+ | 1 | GND | - | 2 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 3 | DSI_CK_P | DSI | 4 | TOUCH_INT | Interrupt out | +------+--------------+------------+-------+--------------+-----------------+ | 5 | DSI_CK_N | DSI | 6 | GND | - | +------+--------------+------------+-------+--------------+-----------------+ | 7 | GND | - | 8 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 9 | DSI_D0_P | DSI | 10 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 11 | DSI_D0_N | DSI | 12 | GND | - | +------+--------------+------------+-------+--------------+-----------------+ | 13 | GND | - | 14 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 15 | DSI_D1_P | DSI | 16 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 17 | DSI_D1_N | DSI | 18 | GND | - | +------+--------------+------------+-------+--------------+-----------------+ | 19 | GND | - | 20 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 21 | BLVDD(+5V) | - | 22 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 23 | BLVDD(+5V) | - | 24 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 25 | - | - | 26 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 27 | BLGND | - | 28 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 29 | BLGND | - | 30 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 31 | - | - | 32 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 33 | - | - | 34 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 35 | - | - | 36 | 3.3V | - | +------+--------------+------------+-------+--------------+-----------------+ | 37 | - | - | 38 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 39 | - | - | 40 | I2C_SDA | I2C | +------+--------------+------------+-------+--------------+-----------------+ | 41 | - | - | 42 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 43 | - | - | 44 | I2C_SCL | I2C | +------+--------------+------------+-------+--------------+-----------------+ | 45 | - | - | 46 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 47 | - | - | 48 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 49 | DSI_TE | DSI | 50 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 51 | - | - | 52 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 53 | BL_CTRL | GPIO | 54 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 55 | - | - | 56 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 57 | RESET | GPIO | 58 | - | - | +------+--------------+------------+-------+--------------+-----------------+ | 59 | - | - | 60 | 1.8V | - | +------+--------------+------------+-------+--------------+-----------------+

Requirements

Your board needs to have a mipi_dsi device tree label to work with this shield.

Usage

The shield can be used in any application by setting SHIELD to st_lcd_dsi_mb1835 and adding the necessary device tree properties.

Set --shield "st_lcd_dsi_mb1835" when you invoke west build. For example:

.. zephyr-app-commands:: :zephyr-app: samples/drivers/display :board: stm32u5g9j_dk1 :shield: st_lcd_dsi_mb1835 :goals: build

You can test both the display and the capacitive touch using the :zephyr:code-sample:draw_touch_events sample:

.. zephyr-app-commands:: :zephyr-app: samples/subsys/input/draw_touch_events :board: stm32u5g9j_dk1 :shield: st_lcd_dsi_mb1835 :goals: build

This sample renders a cross that follows your finger and is a quick way to verify that the panel, LTDC, and touch controller are wired and configured correctly on STM32U5G9J-DK1 with this shield.

References

  • STM32U5G9J-DK1 User Manual <https://www.st.com/resource/en/user_manual/um2967-discovery-kits-with-stm32u5x9nj-mcus-stmicroelectronics.pdf>_

  • MB1835 Schematic (Rev B-01) <https://www.st.com/resource/en/schematic_pack/mb1835-vdd1v8-b01-schematic.pdf>_