This paper describes the use of FPGAs to add a LCD and GUI display to any embedded system. Unlike fixed processor device implementations, this approach is scalable and can support any display interface. Graphics can be generated by any external processor, an embedded processor, or a hardware graphics acceleration engine integrated into the same FPGA design as the display graphics controller. The benefits of FPGA implementation and available tools and IP are described, and links to reference designs and third-party solution providers are given.
Introduction
Graphical displays are increasingly popular for many new applications and industries due to the dramatic increase in the use of GUIs in mass applications such as PCs, phones, PDAs, and other consumer devices. Put simply, users expect a GUI with every application and see great value in the ease of use that this delivers. A second factor is the cost reduction that comes with high-volume manufacturing, with the small and medium display market expected to reach 3.3B units and more than $27B per year in 2009/10. These volumes have resulted in a significant drop in display prices and an increase in the quality, resolutions, and sizes commonly available on the market. As a result, many applications now support the addition of a high-resolution color display and GUI where five to ten years ago it would have just been too expensive to be accepted by the market.
Display technology always has been a dynamic space, as every year LCD developers find new materials and ways to improve the resolution, contrast, viewing angle, and speed of their displays. In addition, there are advances in technology for touch screens, backlighting techniques, and novel displays (such as OLEDs, EPD displays, and even electronic “paper”).
The result of this is that display modules do not have long lifetimes-within a year or two, there will be a better, cheaper, more feature-rich display on the market and the obsolescence process will start for the older module. This may not be an issue for the consumer market space, but many other markets cannot afford to redesign their products so frequently. While the actual display may be still available, there can be problems with sourcing components as manufacturers upgrade to track the latest technology and volume requirements. Even in terms of marketing, the low resolution of an old display can be an issue. Users are less likely to purchase a product that does not meet their constantly increasing expectations of a GUI.
Display Drivers and Controllers
There is a wide range of LCD drivers and controllers on the market today, including pure display drivers (without intelligence of their own), display controllers with integrated display memory (and limited/preset functionality), and general-purpose microcontrollers with integrated LCD controllers. Pure display drivers generally have a high-frequency serial input and continuously require new display data in order to achieve the highest possible refresh frequency. In contrast, a display controller is sent a series of graphical data and control codes, and then it manages the image (usually including fonts), internal memory, and display multiplexing on its own.
Author: Stefano J. Zammattio, Product Manager, European Product Marketing
Mr. Zammattio’s focus is on Altera’s Nios II processor and SOPC Builder products. Mr. Zammattio has been involved in the computing and electronics industry since 1987 and holds a BSc in Physics from the University of Essex and a MSc in Medical Electronics from the University of London.
