Graphics controller cuts cost of embedded displays

March 12, 2013 // By Graham Prophet
Previously known for its range of USB interface chips, FTDI Chip has diversified into the display-controller market with its Embedded Video Engine (EVE), FT800.

The company has applied the same principles to the display sector as it did to USB, according to founder Fred Dart; it has packaged up in an easy-to-use form, all of the functions necessary to implement a small display panel, with resistive touch, and has enabled a significant reduction in cost. With the chip at $2.75 (100,000) and a $9 display, you might build in a complete, small, intelligent display for around $15-$17. Dart outlines how, by devising a display controller entirely programmed using object-oriented techniques, expensive elements normally found in a display system, such as a frame buffer, have been eliminated.

With the FT800, and driving it from a simple microcontroller, you can add an intelligent QVGA or WQVGA TFT display panels to a design. The object oriented approach renders images in a line by line fashion with 1/16th of a pixel resolution. It supports 4-wire resistive touch sensing with built-in intelligent touch detection and an embedded audio processor allowing midi-like sounds combined with pulse code modulation (PCM) for audio playback. The object orientated approach means objects such as images, fonts and audio elements can be easily implemented and manipulated via a low pin-count SPI or I 2C interface. In order for the desired GUI to be realised, you initialise the object memory (up to 256 kBytes) and then control the specified objects and their attributes through construction and interaction of a small display list buffer. As a result of this, even low end (8-bit) MCUs can be used as the host. Up to 2000 objects can be controlled within an 8k byte display list.

The FT800Q is capable of providing 24-bit (true colour) support on an 18-bit interface. It comes preloaded with a useful set of fonts and sounds on its ROM: anti-aliasing mechanisms improve the appearance of the display’s output when rendering lines and complex shapes or when implementing signatures on resistive touch screens: in everyday