Hi All
The uTasker project has long supported a character LCD simulator but from version V1.4 all projects contain monochrome graphical LCD support as well as a foundation for color LCD support. This includes simulation of the LCDs in the uTasker simulator to make development more efficient and more fun.
The following lists some of the history leading up to the decision to add this support and also some basic terminology:
• Graphical monochrome and colour LCDs have become very popular recently with processor evaluation board manufacturers typically adding such a device to their boards; sometimes connected to a dedicated interface such as the LCD controller in the LPC2478, an external memory interface such as the AVR32, via SPI such as some OLEDs on Luminary Micro evaluation boards, or more generally via GPIOs (bit-banging).
• In addition, the semiconductor manufacturers have identified the trend and promote the use of their own devices by supplying graphic libraries as part of demonstration code (Luminary Micro, Atmel, etc.). These graphic libraries are however generally restricted to use with particular microprocessors (licensing) and are not compatible.
• The result of these developments and research into real user requirements led to the decision to add processor-independent graphical LCD support to the µTasker project together with practical graphical LCD simulation support to accelerate project development.
• The first step in the process is the addition of monochrome LCD support including an accurate LCD simulator which can be simply added to all processors via GPIO connections. The initial support is restricted to text and bit-maps but this is generally adequate for most real project use, whereby library functions (such as line or shape drawing) will be added as the LCD project develops.
• In addition to the monochrome graphical LCD support as explained in this section various preparations have been made as foundation for extensions to colour support. The simulator, for example, is already capable of accurately simulating colour LCD controllers as well as processors with internal TFT LCD controller (like the LPC2478). The µTasker projects with such evaluation boards available for them also include a demonstration of this capability although it is not generally contained in the first release of the µTasker V1.4 project. See the following chapters for examples of these where applicable.
• To fully support LCD use various conversion utilities are required. A utility for converting bitmaps as generated with standards graphics programs (paint, etc.) is already included as detailed later in this section.
• Research and practical tests with various LCD types has shown that it is not practical to use a single low level interface. The main reason is due to the memory requirements – a monochrome graphical LCD requires about 1k of RAM in order to back-up the display memory contents, which is generally affordable and thus allows an efficient method of content manipulation and LCD updates based on changed pixels only.
A colour LCD may, on the other hand, require 230k RAM to do the same thing, which is generally not practical. There interfaces are also faster, especially when the display memory is in SDRAM used by an internal LCD controller to automatically refresh, and so there is in this case no advantage in trying to restrict accesses. These conflicting requirements led to the decision to optimise the low level interface to best suit each LCD type and so the monochrome graphical LCD interface was initially designed specifically to suit it’s inherent characteristics.
• Monochrome graphical displays often work very similarly but may have also some special commands to perform special tasks which are restricted to certain controllers. For this reason the first version of the graphical LCD driver concentrates on building a generic foundation based on standard commands. Specific advantages offered by certain display types may be used in the future to optimise operations should this be identified as being beneficial.
• The monochrome graphical LCD is identified from the character LCD in the µTasker project by the name GLCD (Graphical LCD). Colour graphical LCDs are further distinguished by the name CGLCD (Colour Graphical LCD).
The initial version is restricted to supporting fonts and bitmaps (including a useful utility for automatically creating all project widgets in a project file), which represents the fundamentals for the next step of developing the processor-independent uTasker graphics library. LCDs are fun to work with and you may already be quite amazed at what the first simple package can already do...! Get full details in the new LCD user's guide:
http://www.utasker.com/docs/uTasker/uTaskerLCD.PDFHave fun...
Regards
Mark
