Dual-screen Display With RGB and STONE Intelligent TFT LCD Module

Due to the needs of the project, a dual-screen display is needed. The original project uses STM32 + littlevgl + RGB screen display. The PCB board of this project has a serial port to connect to the serial screen, so in order to complete the project quickly, we use STONE Brand STVC050WT-01 serial port screen, this article will introduce how to port littlevgl to the serial port screen and realize dual-screen display with RGB displayer.

STONE Intelligent TFT LCD Module Description

The Intelligent TFT LCD Module with Cortex-M4 32bit CPU can be controlled by Any MCU via simple Hex Instruction through the UART port.

STONE supplies the TOOLBOX Software for engineers to easily & Visually set various functions on Graphical User Interface, Such as Text, Number, Curve, Image switching, Keyboard, progress bar, slider, Dial, Clock, and Touch button, Data storage, USB downloading, Video & Audio. So it is much easy for engineers to adopt TFT-LCD Colorful User Interface & Touch control function on various industrial equipment, And it also can reduce much Development Time and Cost.

littlevgl Description
The LVGL is a lightweight embedded library for displays and touchscreens providing everything required to build fully featured-embedded GUIs.

1. Small fooprint:64 kB flash and 8 kB RAM are enough for a simple user interface.

2. Many widgets: Choose from 30+ ready-to-use widgets and customize them with ease.

3. Any platform: Use LVGL on any platforms, such as STM32, NXP LPC, or i.MX, PIC, Arduino, ESP32, Raspberry, and so on.

4. MicroPython: Do you like Python? Create your UI in MicroPython with LVGL.

5. Any display: Drive monochrome, OLED, TFT displays, monitors, or any other displays.

6. Open source, free, c, LVGL is hosted on GitHub with an MIT license, It's really free to use

STM32F429 description

Core: Arm® 32-bit Cortex®-M4 CPU with FPU, Adaptive real-time accelerator (ART Accelerator™) allowing 0-wait state execution from Flash memory, frequency up to 180 MHz, MPU, 225 DMIPS/1.25 DMIPS/MHz (Dhrystone 2.1), and DSP instructions

1. Memories

– Up to 2 MB of Flash memory organized into two banks allowing read-while-write

– Up to 256+4 KB of SRAM including 64-KB of CCM (core coupled memory) data RAM

– Flexible external memory controller with up to 32-bit data bus: SRAM, PSRAM, SDRAM/LPSDR SDRAM, Compact Flash/NOR/NAND memories

2. LCD parallel interface, 8080/6800 modes

3. LCD-TFT controller with fully programmable resolution (total width up to 4096 pixels, total height up to 2048 lines, and pixel clock up to 83 MHz)

4. Chrom-ART Accelerator™ for enhanced graphic content creation (DMA2D)

5. Clock, reset and supply management

– 1.7 V to 3.6 V application supply and I/Os

– POR, PDR, PVD, and BOR

– 4-to-26 MHz crystal oscillator

– Internal 16 MHz factory-trimmed RC (1% accuracy)

– 32 kHz oscillator for RTC with calibration

– Internal 32 kHz RC with calibration

6. Low power

– Sleep, Stop and Standby modes

– VBAT supply for RTC, 20×32 bit backup registers + optional 4 KB backup SRAM

7. 3×12-bit, 2.4 MSPS ADC: up to 24 channels and 7.2 MSPS in triple interleaved mode

8. 2×12-bit D/A converters

9. General-purpose

DMA: 16-stream DMA controller with FIFOs and burst support

10. Up to 17 timers: up to twelve 16-bit and two 32-bit timers up to 180 MHz, each with up to 4 IC/OC/PWM or pulse counter and quadrature (incremental) encoder input

11. Debug mode

– SWD & JTAG interfaces

– Cortex-M4 Trace Macrocell™

12. Up to 168 I/O ports with interrupt capability

– Up to 164 fast I/Os up to 90 MHz

– Up to 166 5 V-tolerant I/Os

13. Up to 21 communication interfaces

– Up to 3 × I2C interfaces (SMBus/PMBus)

– Up to 4 USARTs/4 UARTs (11.25 Mbit/s, ISO7816 interface, LIN, IrDA, modem control)

– Up to 6 SPIs (45 Mbits/s), 2 with muxed full-duplex I2S for audio class accuracy via internal audio PLL or external clock

– 1 x SAI (serial audio interface)

– 2 × CAN (2.0B Active) and SDIO interface

14. Advanced connectivity

– USB 2.0 full-speed device/host/OTG controller with on-chip PHY

– USB 2.0 high-speed/full-speed device/host/OTG controller with dedicated DMA, on-chip full-speed PHY and ALPI

– 10/100 Ethernet MAC with dedicated DMA: supports IEEE 1588v2 hardware, MII/RMII

15. 8- to 14-bit parallel camera interface up to 54 Mbytes/s

16. True random number generator

17. CRC calculation unit

18. RTC: subsecond accuracy, hardware calendar

19. 96-bit unique ID

First use solder to remove the place as shown in the figure, which means UART using TTL level. If short it means RS232, as we are using TTL level, so we disconnect it. (as shown in the 1st picture)

Connect the displayer with the connector provided by STONE, disconnect the jumper cap, and connect the voltage to 12v DC voltage, the red wire is connected to the RDX of STM32F429 and the yellow wire is connected to the TXD of STM32F429, as shown in the 2nd picture.

At this point, our hardware circuit has been connected. (as shown in the 3rd picture)

Open "STONE TOOL 2019.exe" and create a new project named STONE as shown in the 1st picture.

Then you will get the following window. (as shown in the 2nd picture)

click the right key to remove the 0.jpg and add the bkgd.jpg picture which creates by Photoshop with the back background. (as shown in the 3rd picture)

click compiling button to build the project. Then plug in the USB port. (as shown in the 4th picture)

if you see these words on the screen, it means you can download the software now. (as shown in the 5th picture)

Click the download online button it will show the Download Configuration File dialog, you can see USB has been detected, and click the Download button. (as shown in the 6th picture)

So far, the Stone module part has been finished. now we are going to design the STM32 part, as we have implement littltevgl, so here we only descript how the added support for the intelligent TTF LCD module. ok, let's go.
First new "drv_lcd_stone.c" and implement two interface, one is "lcd_stone_init" the other is "lcd_stone_color_fill"

compile the code and download the software.

Now we have finished our project, it only takes a few hours to finish it. so the STONE Intelligent TFT LCD Module is very efficient and convenient.