This driver supports systems with passive color displays connected to an LCD controller in monochrome mode. The LCD controller is assumed to have a linear video memory organization and to work in a 16 gray-scale mode, yielding 16 levels of intensity for every sub-pixel and therefore 16*16*16 = 4096 colors on the display. If the LCD controller supports colors, it is usually better to use it in color mode (with the LCDLin diver), as this more efficient. An example of where this driver is used is the LCD controller built-into the Cirrus Logic EP7312.

Supported hardware

Controllers

Any Passive color display connected to an LCD controller with linear memory operating in monochrome mode.

Bits per pixel

Supported color depth is 12 bpp.

Interfaces

The driver supports a 16 bit full bus interface from the CPU to the LCD controller.

Display data RAM organization

This driver supports a 12 bpp memory area for color displays. The pictures above show the dependence between the memory area handled by the driver and the SEG and COM lines of the LCD.

Additional RAM requirements of the driver

None.

Additional driver functions

None.

Hardware configuration

This driver requires a full bus interface for hardware access as described in Chapter 24: "Low-Level Configuration". The following table lists the macros which must be defined for hardware access:

Example:

A QVGA color display needs the following defines in LCDConf.h:
#define LCD_XSIZE 320
#define LCD_YSIZE 240
The LCD controller needs to be initialized to control a monochrome display of 960x240 resolution.

Additional configuration switches

The following table shows optional configuration switches available for this driver:

Special requirements for certain LCD controllers

The driver needs to work in one of the following fixed palette modes:

• 44412 (default if working in 12bpp mode)
• 444121
• 44416

The driver does not work with other palettes.