4D Systems Pixxi-LCD Screens
The Pixxi-LCD screens are the fifth generation of intelligent screens from 4D Systems. They are built around the Pixxi GPU, with two variants: Pixxi-28 and Pixxi-40.
The real innovation from the pixxiLCD series is the unusual shapes: circle, square, elongated rectangle.
The screens were sampled by 4D Systems. |
Hardware
The screen connects to the MCU through a standard UART port. The flat cable connects to a bridge, which exposes 5 standard male pins. The 5-way cable includes VCC, GROUND, RX, TX and /RESET. Although labeled +5V, the VCC pin accepts +3.3V.
There are two available adaptors to connector the 30-way flat cable from the screen:
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The golden pads of the cable should be on top, and the black part should face the boards.
The connection may be misleading, as the cable mentions the TX and RX relevant to the board and not the screen. Actually, the adapter performs the crossing between RX and TX: board's RX goes to screen's TX, and so for board's TX to screen's RX. However, when the cable is plugged in the adapter, it hides the silkscreen with the labels of the signals. |
The screens includes a push-pull micro-SD card slot and a massive 16MB Flash memory.
The screens come pre-configured with the firmware with serial connection for SPE mode, and Flash memory for mass storage. To use the SD card as mass storage instead, a specific firmware needs to be flashed. The procedure How to Update PmmC for Pixxi is detailed and easy to follow, but the required tools only run on Windows. |
Software
The screen can be used in multiple modes, stand-alone board or slave screen.
As always, 4D Systems provides an extensive collection of Application Notes. The Pixxi-Serial-Arduino-Library eases the use of the screen on an Arduino-compatible board. All the codes of the functions are listed in a header file specific to the Pixxi screens. I only had to replace the Diablo16 header file by this new one for Pixxy, and my LCD_screen Library Suite ran immediately with the new Pixxi screens. Similarly, the same code can run on different screens, provided the graphics are context-dependent. Here, the clock fits into a circle, a square and a rectangle. Alas, the Pixxi screens face the same limitations for the extended set of characters like éàûôù. And the Pixxi screens come with three built-in fonts only instead of ten with the Diablo16 GPU. The application note Serial Displaying Third Party Fonts FAT16 (4D-AN-00089) provides the same procedure for generating an external font saved on the micro-SD card. However, this procedure requires 4D Workshop, which runs on Widows only. |
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Projects
The unusual shapes of the Pixxi screens inspired me the following projects:
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The screens are crisp and clear, the colours stable and vibrant, and the touch precise and responsive, although no interrupt is generated. |
Conclusion
With this new generation, 4D Systems improves its GPUs and screens. The 5th generation relies on a more powerful GPU and offers unusual shapes, perfect for specific use cases.
The only limitation of the screen comes from the tools, only available for Windows. This restriction could be easily solved, should 4D Systems provide some of them online, like the font generator. The Pixxi screens may appear expensive, but they provide a GPU and the Visi-Genie environment for fast development of graphic user interfaces. The great documentation and multiple application notes are of great help to start a new project. |
Pros
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Cons
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Wrap-Up
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Links
Posted: 12 Nov 2020
Edited: 25 Nov 2020