4D Systems gen4-uLCD-35DCT-CLB
Hardware
The screen connects to the MCU through a standard UART port. The 5-way cable includes +5V, GROUND, RX, TX and /RESET.
There are two available adaptors to connector the 30-way flat cable from the screen:
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The silver pads of the cable should be on top, and the blue 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 boards'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. |
I've faced two series of issues with the screen, first when connecting the Arduino Adaptor and second when using faster boards.
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The board includes a sliding micro-SD card slot.
The animation on the right details how to insert and remove a card. |
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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 Diablo16-Serial Arduino Library eases the use of the screen on an Arduino-compatible board. I faced no major difficulties adapting the Serial_LCD Library Suite to this gen4 screen, except for the two issues mentioned earlier (reversed /RESET and fast MCUs). |
As with previous generations, the built-in fonts of the gen4-uLCD-35DCT except one don't include the extended set of characters like éàûôù. Only font number 11 called EGA and sized 8x12 includes extended characters, although on a non-standard charset. Actually, it is the MS-DOS code page 437! This is a serious limitation for international applications.
Using extended characters requires to generate an external font saved on the micro-SD card. The application note Serial Displaying Third Party Fonts FAT16 (4D-AN-00089) explains how to perform it. However, this procedure requires 4D Workshop, which runs on Widows only. Extended characters are missing from an external font when selecting too large a size, as Verdana 24, because of the limited amount of RAM for the Diablo16 GPU, which loads the external font. |
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Conclusion
Generation after generation, 4D Systems improves its GPUs and screens. The 4th generation relies on a more powerful GPU and features a slim and sleek design, perfect for integration with the bezel.
The screen is very bright and crisp. Density reaches 166 dpi for the 480x320 3.5" screen. 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 gen4 screens may appear expensive, but they provide a GPU and the Visi-Genie environment for fast development of graphic user interfaces. |
Pros
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Cons
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Wrap-Up
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Links
Posted: Aug 09, 2017
Edited: Aug 11, 2017