Defining the Architecture

The legato_flash application uses the USB file systems in MPLAB Harmony and the USB driver to scan the MSD for a .hex file with resources and reads them sector by sector and programs the external non-volatile SQI memory. The Graphics Library is used to render graphics to the display. Using the DMA, the Low-Cost Controllerless (LCC) Display Driver continuously transfers frame data from the frame buffer out to the LCD display.

The application also features user touch input through the integrated touch screen on the display panel. Touch input from the touch controller goes through the I2C port, and the Input System Service acquires the touch input information from the Touch and I2C drivers. The Input System Service sends touch events to the Graphics Library, which processes these events and updates the frame data accordingly.

This configuration runs on the PIC32MZ EF Curiosity 2.0 with RGB565 GFX Interface board and WQVGA display. A 16-bit RGB565 frame buffer is stored in the internal SRAM, and the Low Cost Controller-less (LCC) display driver is used to manage the DMA that transfers the framebuffer contents to the display via the EBI peripheral.

User touch input on the display panel is received thru the PCAP 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 thru the Input System Service.

The USB peripheral is setup in MSD Host mode with the File System service support. It scans for a file named SQI.hex when a USB MSD device is connected. The application reads the hex data from the file and decodes it with a hex decoder into binary data. The binary is written to external non-volatile memory via the QSPI peripheral configured with the SST26 driver.

Demonstration Features

Legato Graphics Library
Input system service and touch driver
Time system service, timer-counter peripheral library and driver
Low-Cost Controller-less (LCC) display driver
16-bit RGB565 color depth support (65535 unique colors)
EBI peripheral library and driver
I2C peripheral library and driver
SST26 QSPI driver
USB MSD driver (Host Mode)
File System
Images and Fonts for user interface stored in internal flash

Creating the Project Graph

The Project Graph diagram shows the Harmony 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 PIC32MZ EF Curiosity 2.0 BSP and Legato Graphics w/ PDA TM4301B 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 the touch controller.

Disable VBUS function for USB High Speed Driver

For SPI Flash access, make sure all 6 pins for QSPI is mapped.

To drive the USB peripheral, make sure UPLL is enabled with the 40x multiplier, with USB FS Clock output 48 MHz.

Building the Application

The parent directory for this application is gfx/apps/legato_flash. To build this application, use MPLAB X IDE to open the gfx/apps/legato_flash/firmware/legato_fl_mzef_cu_tm4301b.X project file.

The following table lists configuration properties:

Project Name	BSP Used	Graphics Template Used	Description
legato_fl_mzef_cu_tm4301b.X	PIC32MZ EF Curiosity 2.0	Legato Graphics w/ PDA TM4301B Display	PIC32 MZ EF Curiosity 2.0 with maXTouch Curiosity Pro 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 Harmony Configurator to regenerate the application code, use the "ALL" merging strategy and do not remove or replace the custom code.

Configuring the Hardware

PIC32MZ EF Curiosity 2.0 with the 4.3” WQVGA PCAP Touch Display Configure the hardware as follows:

Attach the RGB565 GFX Interface Card to the J601 connector on the PIC32MZ EF Curiosity 2.0 board.
Connect the ribbon cable from the WVGA display to the J2 connector on the RGB565 GFX Interface card.
Connect a USB cable from the host computer to the DEBUG USB port on the PIC32MZ EF Curiosity 2.0 board. This USB connection is used for code download and debugging.
Connect 5.5V power supply to the PIC32MZ EF Curiosity 2.0 board. This is needed for the USB VBUS detection.
Connect the USB MSD device to the ‘Target USB’ USB micro port. This can be connected before or at any point after the application is powered-on.

The final hardware setup should be:

Running the Demonstration

When power-on is successful, without a USB MSD device or SD MMC device attached to the Target USB port the demonstration will display a screen with the message No valid storage mediums found. Please insert a USB device or SD Card:

If a valid USB MSD device is connected, the display will a USB button. LED1 (red) will light up also.

If a valid SDMMC device is connected, the display will a SD button. LED2 (yellow) will light up also.

Make sure the USB MSD device or the SD MMC device has FAT32 file system format and a valid external resources file named precisely SQI.hex is copied inside.

Press and release the SD button or the USB button on-screen. The application will initiate the data transfer on release of the button. Depending on the size of SQI.hex file (greater than 500 kilobytes), the application may freeze with no visual feedback, upwards of 30 seconds. It will then display a progress bar to indicate the transfer. The transfer completes when the progress bar is filled. The application will then display a button with OK.