legato_qs_9x75_eb_raspi_7inch.X
Defining the Architecture
This application demonstrates multi-layer WVGA graphics using DDR3 memory.
User touch input on the display panel is received through the capacitive touch controller, which sends a notification to the Touch Input Driver. The Touch Input Driver reads the touch information over I2C and sends the touch event to the Graphics Library through the Input System Service.
Demonstration Features
- Legato Graphics Library
- Reference application for the SAM9X75-DDR3-EB Early Access Evaluation Board
- 24-bit color, multi-layer, WVGA (800x480) screen design
- Time system service, RTT peripheral library and driver
- Graphics Acceleration using integrated display controller (XLCDC)
- GFX2D GPU Driver Support
- Raspberry Pi Touch Display driver
Creating the Project Graph
The Project Graph diagram shows the Harmony 3 components that are included in this application. Lines between components are drawn to satisfy components that depend on a capability that another component provides.
Adding the SAM 9X75 Evaluation Board BSP and Legato Graphics w/ RPi Touch Display Graphics Template component into the project graph will automatically add the components needed for a graphics project and resolve their dependencies. It will also configure the pins needed to drive the external peripherals like the display and touch controller.
Building the Application
The parent directory for this application is gfx/apps/legato_quickstart. To build this application, use MPLAB X IDE to open the gfx/apps/legato_quickstart/firmware/legato_qs_9x75_eb_rpi_7inch.X project folder and press F11. A successful build will generate a harmony.bin file in dist/dsi_xlcdc_rgba8888_rpi_9x75_wvga/production in the project folder.
The following table lists configuration properties:
| Project Name | BSP Used | Graphics Template Used | Description |
|---|---|---|---|
| legato_qs_9x75_eb_rpi_7inch.X | SAM 9X75 Evaluation Board BSP | Legato Graphics w/ RPi Touch Display | SAM9X75-DDR3-EB Early Access Evaluation Board and Raspberry Pi Touch Display MIPI DSI Display |
NOTE: This application may contain custom code that is marked by the comments // START OF CUSTOM CODE … and // END OF CUSTOM CODE. When using the MPLAB Code Configurator to regenerate the application code, do not remove or replace the custom code.
Configuring the Hardware
Configure the hardware as follows:
- Connect the power pins of the Raspberry Pi Touch Display (5V and GND) to the SAM9X75 Evaluation Board’s mikroBus header using jumpers as shown in the image below.
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Connect the display to the evaluation board using a 22-pin to 15-pin DSI FFC cable. Connect the 15-pin side to the display with the contacts facing up and the 22-pin side with the contacts facing away from flip-lock as shown in the image.
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Take an SD Card formatted with the FAT32 file system and copy the boot.bin binary file from this location. Also copy the harmony.bin file you generated from the “Building the Application” section.
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Insert the SD card into the SDMMC0 slot on the SAM9X75-DDR3-EB Early Access Evaluation Board and power up the board by connecting a USB cable (5V/1A recommended) to the USB port or an adapter to the barrel jack (5V/1A recommended, Center Positive).
Running the Demonstration
The LCD should display a simple menu with images, text, and a button on successful power-on. See reference image.
NOTE: This display has non-square pixels. Therefore, images may appear slightly stretched across the width of the display. You can fix this by scaling only the width of the image assets down from 100% to 92.47% in your favourite image editor.